prl technical workshop

PRL Technical Workshop

May Contain U.S. Export Controlled Information

PRL Technical WorkshopPRL Technical Workshop

Student Guide

80-W0902-1 Rev C

For Reliance Communications internal purposes only. Not to be shared externally.

Material Use RestrictionsThese written materials are to be used only in conjunction with the associated instructor-led class. They are not intended to be used solely as reference material.

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PRL Technical Workshop 80-W0902-1 Rev CTable of Contents




About CDMA University

CDMA University training is offered by the CDMA Development Group (CDG) in association with QUALCOMM. This partnership strives to continually improve training needs assessment and outreach to the CDMA community.

CDMA University (“CDMAU”) offers the advanced technology training solutions you need to stay on the cutting edge of wireless technology.

Visit www.cdmauniversity.com for more information about individual training products and international training centers, along with a complete list of classes – all developed and delivered by CDG member company QUALCOMM, the pioneers of CDMA.

CDMA University: www.cdmauniversity.comCDMA Development Group (CDG): www.cdg.orgQUALCOMM: www.qualcomm.com

Notes

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Where Can I Learn More?

International Roaming (2 days)

Packet Data Roaming (0.5 day)

SMS Roaming (0.5 day)

Authentication (0.5 day)

Want to learn more?CDMA University offers additional in-depth technical training related to this course. To learn more about this or related topics, sign up for the following courses.

To check out the schedules for these courses and enroll, go to:www.cdmauniversity.com

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CDMA Courses from CDMA University

For the latest information on all CDMA courses, visit www.cdmauniversity.com

Notes



May Contain U.S. Export Controlled Information vi

Table of Contents Section 1: Course Overview .................................................................. 1-1PRL Technical Workshop – Course Overview........................................ 1-2 Reference Documentation........................................................................ 1-3 Section 2: Introduction to Preferred Roaming Lists .......................... 2-1Section Learning Objectives .................................................................... 2-2 Identification of a CDMA Network......................................................... 2-3 What is a Preferred Roaming List (PRL)?............................................... 2-7 Organization of a PRL Database.............................................................. 2-8 Is a PRL Always Required?..................................................................... 2-9 Where is the PRL and How Does it Get There? .................................... 2-10 Updating the PRL Over the Air ............................................................. 2-11 What Does a PRL Look Like? ............................................................... 2-13 Understanding the Properties of a PRL ................................................. 2-14 Acquisition Table................................................................................... 2-15 Cellular Analog Acquisition Record...................................................... 2-16 Cellular CDMA (Standard Channels) Acquisition Record................... 2-17 What are Cellular CDMA Standard Channels? ..................................... 2-18 Cellular CDMA (Custom Channels) Acquisition Record .................... 2-19 Cellular CDMA Preferred Acquisition Record...................................... 2-20 PCS CDMA Blocks and Channels......................................................... 2-21 PCS CDMA (Using Blocks) Acquisition Record.................................. 2-22 PCS CDMA (Using Channels) Acquisition Record .............................. 2-23 System Table ........................................................................................ 2-24 System Table Record ............................................................................. 2-25 Size Matters ........................................................................................ 2-27 Introduction to PRL – Section Review .................................................. 2-28 Section 3: How the PRL is Used ........................................................... 3-1Section Learning Objectives .................................................................... 3-2 System Determination.............................................................................. 3-3 System Preferences .................................................................................. 3-4 System Scanning...................................................................................... 3-6 Acquisition Table Expansions ................................................................. 3-7 About Guard Band Channels ................................................................... 3-8 Most Recently Used Table....................................................................... 3-9 Scan Lists ........................................................................................ 3-10 Normal and Better Service Scan Lists ................................................... 3-11 System Lost Scan List............................................................................ 3-12 How Long is a Scan? ............................................................................. 3-13 System Selection.................................................................................... 3-14



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System Types ........................................................................................ 3-15 When System Selection Occurs ............................................................. 3-16 Types of System Selection..................................................................... 3-17 Identifying an Acquired System in the System Table .......................... 3-18 Applying Priorities in Selecting a System ............................................. 3-19 Applying Priority ................................................................................... 3-21 Multi-GEO SIDs .................................................................................... 3-22 Available System and “Open” PRLs ..................................................... 3-23 Understanding Reselection .................................................................... 3-24 SID, NID, or Band Class Change .......................................................... 3-26 Avoidance of Unusable Systems ........................................................... 3-28 No Selectable System ............................................................................ 3-29 How the Preferred Roaming List is Used – Section Review................. 3-30 Section 4: PRL Process.......................................................................... 4-1 Section Learning Objectives .................................................................... 4-2 Why is a PRL Process Necessary?........................................................... 4-3 PRL Data Source Management................................................................ 4-4 Change Identification Analysis................................................................ 4-5 PRL Production........................................................................................ 4-6 PRL Testing .......................................................................................... 4-7 Release and Distribution .......................................................................... 4-8 PRL Distribution...................................................................................... 4-9 Non-Customer Targets .............................................................. 4-10 Distribution – In-Service Targets .......................................................... 4-11 PRL Process Timeline............................................................................ 4-12 PRL Process – Section Review.............................................................. 4-13 Section 5: PRL Design ........................................................................... 5-1 Section Learning Objectives .................................................................... 5-2 PRL Constraints ....................................................................................... 5-3 Device Constraints ................................................................................... 5-4 Some Potential Device Constraints.......................................................... 5-6 Policy Constraints .................................................................................... 5-7 Mitigation Constraints ............................................................................. 5-8 Coverage Plan .......................................................................................... 5-9 In the PRL.................................................................................. 5-10 Partner Priority in the PRL .................................................................... 5-11 Policy Constraints – PRL Structure ....................................................... 5-12 Design Aspects to Consider ................................................................... 5-13 GEO Design ........................................................................................ 5-14 Information for PRL Production ........................................................... 5-15 Information from a Roaming Partner..................................................... 5-16 Change Analysis .................................................................................... 5-17



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PRL Design System Table.............................................................................. 5-18 Acquisition Table....................................................................... 5-19 PRL Tools The PRL Editor .......................................................................... 5-20 Spreadsheet ............................................................................... 5-21 PRL Tool Suite – An Excel Add-in ........................................... 5-22 PRESTO ........................................................................................ 5-23 PRL Auditing ........................................................................................ 5-24 PRL PREDICATE ................................................................................. 5-25 PRL PREDICT....................................................................................... 5-26 PRL Design – Section Review............................................................... 5-27 Section 6: PRL Design Checks.............................................................. 6-1 Section Learning Objectives .................................................................... 6-2 PRL Design Issues ................................................................................... 6-3 Potential Reselection Exits ...................................................................... 6-4 Coverage Holes in GEOs ......................................................................... 6-5 Presence of AMPS Systems..................................................................... 6-6 Presence of Unlisted SIDs ....................................................................... 6-7 Inconsistent Preferences within GEOs..................................................... 6-8 Duplicate System Records ....................................................................... 6-9 PRL Design Checks – Section Review.................................................. 6-10 Section 7: Hybrid 1X / EV-DO PRL .................................................... 7-1 Section Learning Objectives .................................................................... 7-2 The PRL with CDMA2000 1xEv-DO ..................................................... 7-3 IS-683C PRL .......................................................................................... 7-4 Sector ID in 1xEV-DO............................................................................. 7-5 Subnet ID in the 1xEV-DO PRL ............................................................. 7-6 IS-683C PRL Structure ............................................................................ 7-7 IS-683C – The New Records ................................................................... 7-8 1xEV-DO Acquisition Record ................................................................. 7-9 IS-683C System Record Structure ......................................................... 7-10 1xEV-DO System Record...................................................................... 7-11 1xEV-DO System Identification............................................................ 7-12 Association of IS-856 Systems .............................................................. 7-13 Hybrid 1X / EV-DO PRL – Section Review ......................................... 7-14 Section 8: Use of the Hybrid 1X / EV-DO PRL................................... 8-1 Section Learning Objectives .................................................................... 8-2 Hybrid System Determination ................................................................. 8-3 Device Settings & Modes of Operation ................................................... 8-4 1xEV-DO Scanning ................................................................................. 8-5 Hybrid System Selection.......................................................................... 8-7 EV-DO System Selection ...................................................................... 8-10 Avoidance of Unusable 1xEV-DO Systems .......................................... 8-11



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System Loss ........................................................................................ 8-12 Use of the Hybrid 1X / EV-DO PRL – Section Review........................ 8-13 Section 9: Writing a Hybrid 1X / EV-DO PRL................................... 9-1 Section Learning Objectives .................................................................... 9-2 Things to Consider When Writing an EV-DO PRL ................................ 9-3 1xEV-DO PRL Design Considerations ................................................... 9-4 Varying EV-DO Coverage....................................................................... 9-5 How to Write an EV-DO PRL................................................................. 9-6 Association of IS-856 Systems ................................................................ 9-8 Writing a Hybrid 1X / EV-DO PRL – Section Review ........................... 9-9 Section 10: PRL Enhancements.......................................................... 10-1 Section Learning Objectives .................................................................. 10-2 The Need for PRL Enhancements.......................................................... 10-3 CDG Resolution for PRL Enhancements .............................................. 10-4 Identifying a System .............................................................................. 10-5 PRL Enhancements – How They Work................................................. 10-6 Use of Existing Standards...................................................................... 10-7 Implementing the CDG Resolution ....................................................... 10-8 CDG Coordination Roles....................................................................... 10-9 PRL Enhancements Impacts on Infrastructure ......................................................... 10-10 Impacts on Handsets ............................................................... 10-11 Aspects of Operator Implementation ...................................... 10-12 Benefits .................................................................................... 10-13 PRL Enhancements – Section Review................................................. 10-14



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Acronyms and Abbreviations

Acronym / Abbreviation Description

1xEV-DO CDMA2000 evolution, data optimized

1x/IS-95 CDMA2000 evolution for voice and medium rate data

1xRTT 3G wireless technology based on the CDMA platform. The 1x in 1xRTT refers to 1x the number of 1.25MHz channels. The RTT in 1xRTT stands for Radio Transmission Technology

3G Third-generation wireless system

3GPP2 Third Generation Partnership Project 2

AC Alternating Current

AMPS Advanced mobile phone system

ANSI American National Standards Institute

ANSI-41 A worldwide network signaling standard used in CDMA systems

AT Access terminal

AVRU Automated voice response unit

BIDS Billing identification (ID) numbers

BTA Basic trading area

BSE Base station emulators

BTS Base transceiver station

CAIT QUALCOMM CDMA air interface tester

CCITT Consultative Committee on International Telegraphy and Telephony. Now replaced by ITU-T

CCLM CDMA channel list message

CDG CDMA Development Group

CDMA Code division multiple access

CDMA-2000 A family of air interface standards evolved from IS-95. The family includes evolutionary steps such as 1X, EV-DO, EV-DO Rev A, etc.

CSC Customer service center

DC Direct Current

DO Data optimized (as in EV-DO)

Ec/Io Energy per chip divided by energy of interference

EIA Electronics Industry Association


PRL Technical WorkshopSection 1: Course Overview

80-W0902-1 Rev C

1-1May Contain U.S. Export Controlled Information


Section 1-1


Section 1:Course Overview

1SECTION

Course Overview

Notes



80-W0902-1 Rev C



Section 1-2


PRL Technical Workshop –Course Overview

1. Course Overview2. Introduction to Preferred Roaming Lists3. How the PRL is Used4. PRL Process5. PRL Design6. PRL Design Checks7. Hybrid 1X / EV-DO PRL8. Use of the Hybrid 1X / EV-DO PRL9. Writing a Hybrid 1X / EV-DO PRL10. PRL Enhancements

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Section 1-3


Reference Documentation

Course R

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964AB_00_revD.emf


TIA Name 3GPP2 Name Title / Download Location

IS-856-0 C.S0024-0 v2.0 cdma2000 High Rate Packet Data Air Interface Specification (1.8MB) http://3gpp2.org/Public_html/specs/C.S0024_v2.0.pdf

IS-856-1 C.S0024-0 v3.0 cdma2000 High Rate Packet Data Air Interface Specification (2.6MB) http://3gpp2.org/Public_html/specs/C.S0024-0_v3.0.pdf

IS-856-2 C.S0024-0 v4.0 cdma2000 High Rate Packet Data Air Interface Specification (2.3MB) http://3gpp2.org/Public_html/specs/C.S0024-0_v4.0.pdf

TIA-856-A C.S0024-A v1.0 cdma2000 High Rate Packet Data Air Interface Specification (5.4MB) http://3gpp2.org/Public_html/specs/C.S0024-A_v1.0_040331.pdf

TIA-1030 C.S0057-0 v1.0 Band-class Specification for CDMA-2000 Spread Spectrum Systemshttp://3gpp2.org/Public_html/specs/C.S0057-0_v1.0_020904.pdf

ANSI/TIA/EIA 41-D N.S0005-0 v1.0 Cellular Radio Telecommunications Intersystem Operationhttp://3gpp2.org/Public_html/specs/N.S00050_(Cellular_Intersystem)_v1.0_pv.pdf

IS-725-A N.S0011-0 v1.0 OTASP and OTAPAhttp://3gpp2.org/Public_html/specs/N.S0011-0_v1.0.pdf

ANSI/TIA/EIA-TSB-29D N.S0017-B v1.0 International Implementation of Wireless Telecommunication SystemsCompliant With ANSI/TIA/EIA-41http://3gpp2.org/Public_html/specs/N.S0017-B.pdf



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Section 1-4


Reference Documentation (continued)

Course R

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964AB_00_revD.emf


TIA Name 3GPP2 Name Title / Download Location

TIA/EIA IS-2000 C.S0001-0 v3.0 Introduction to cdma2000 Spread Spectrum Systems Release 0http://3gpp2.org/Public_html/specs/C.S0001-0_v3.0.pdf

IS-683-A C.S0016-0 v1.0 Over-the-Air Service Provisioning of Mobile Stations in Spread Spectrum Systems http://3gpp2.org/Public_html/specs/C.S0016-0with3Gcover.pdf

TIA-683-B C.S0016-A v2.0 Over-the-Air Service Provisioning of Mobile Stations in Spread Spectrum Systemshttp://3gpp2.org/Public_html/specs/C.S0016-A_v2.0.pdf

TIA-683-C C.S0016-B v1.0 Over-the-Air Service Provisioning of Mobile Stations in Spread Spectrum Standards http://3gpp2.org/Public_html/Specs/C.S0016-B_v1.0.pdf

TIA-683-D C.S0016-C v1.0 Over-the-Air Service Provisioning of Mobile Stations in Spread Spectrum Standards (4.7MB)http://3gpp2.org/Public_html/specs/C.S0016-C_v1.0_041025.pdf

IS-820 C.S0023-0 v2.0 Removable User Identity Module (RUIM) for cdma2000 Spread Spectrum Systems (357 KB) http://3gpp2.org/Public_html/specs/CS0023-0.pdf

IS-820-1 C.S0023-0 v4.0 Removable User Identity Module for Spread Spectrum Systems (546 KB) http://3gpp2.org/Public_html/specs/C.S0023-0_v4.0.pdf

TIA-820-A-1 C.S0023-A v1.0 Removable User Identity Module for Spread Spectrum Systems (558 KB) http://3gpp2.org/Public_html/specs/C.S0023-A_v1.0.pdf

TIA-820-A-1 C.S0023-A v2.0 Removable User Identity Module for Spread Spectrum Systems (846 KB) http://3gpp2.org/Public_html/specs/C.S0023-A_v2.0_021004.pdf

TIA-820-A-2[E] C.S0023-A v3.0 Removable User Identity Module for Spread Spectrum Systems (799 KB) http://3gpp2.org/Public_html/specs/C.S0023-A_v3.0_041220.pdf

TIA-820-B C.S0023-B v1.0 Removable User Identity Module for Spread Spectrum Systems (830 KB) http://3gpp2.org/Public_html/specs/C.S0023-B_v1.0_040426.pdf


PRL Technical WorkshopSection 2: Introduction to Preferred Roaming Lists

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Section 2-1


Section 2:Introduction to Preferred Roaming Lists

2SECTION

Introduction to

Preferred Roaming Lists

Notes



80-W0902-1 Rev C



Section 2-2


Section Learning Objectives

Understand the identification of CDMA Networks.Describe the purpose of the PRL. Identify the major components of a PRL.Describe the structure of the PRL.List the different types of Acquisition Records.

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80-W0902-1 Rev C



Section 2-3


Identification of a CDMA Network

Regulatory Markets• Markets are divided into Licensed

areas – Cellular Geographic Service Areas (CGSAs)

Licenses • Each license allocates a particular

range of frequencies within a particular band

• There are multiple licenses available in multiple bands for one CGSA

Licensees• Acquire spectrum in one or more

CGSAs to offer commercial service• May not always hold the same

spectrum in adjacent markets

The Market

Cellular Geographic

Service Areas

Regulatory Markets and Frequency Licenses

In the U.S. in the 1980s, authorities mandated a duopoly structure for the fledgling cellular industry in an attempt to protect against anti-competitive behavior. At the outset of this mandate, local wirelinecompanies were automatically granted one of the two licenses in the cellular band in every market in which they provided wireline service (the B Band). The second license (A Band) for each market was initially drawn by lottery and later auctioned. Later PCS Block were also auctioned.

In most countries a regulatory body governs (or licenses) the use of commercial radio frequency spectrum. The regulator generally divides the market up in two domains, a geographic domain and a frequency domain.

The geographic domain divisions, sometimes called regulatory markets, are the physical areas of the country; in the United States they are called Geographic Region Service Areas (GRSA). The frequency domain divisions are the individual licensed frequency allocations. A license is usually the right to use a particular frequency allocation in a particular regulatory market. Thus, if the regulator divides frequency spectrum into 8 bands, and divides the country into 50 markets, then there are potentially 400 licenses.

A licensee can choose to offer retail commercial service and be an operator or to wholesale the capacity to a retail operator. The term ‘operator’ generally means the organization that installs the network and sells service to customers. Regulatory markets may be identified by some kind of geographic and frequency designator which may not have meaning outside of the regulatory context.



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Section 2-4


Identification of a CDMA Network (continued)

Every CDMA system is uniquely identified by the combination of:

• System Identification Code (SID)

• Network Identification Code (NID)

• Mobile Country Code

• Mobile Network Code

• Radio Frequency (Band Class or Channel)

The Market

Cellular Geographic

Service Areas

Operator A’s implementation

of the market

Operator B’s implementation

of the market

Commercial MarketsRegulatory market divisions, while being good administrative tools, may not align with the operator’s commercial markets. Often the commercial market is a combination of a number of licenses which may span many regulatory markets—which may or may not be all in the same frequency band. From the commercial operators perspective a commercial market can mean many things; it can be a city or an area of a city, a county, a state, or some other region defined as a network boundary. In CDMA, every system identifies itself by broadcasting its name. This name comprises its system identification (SID) and its network identification (NID). These identities are configured by the operator. One operator may choose to have all systems in a particular area broadcast the same identity while another may choose a lesser or greater granularity.System Identification CodeThe System Identification code (SID) is a 15-bit binary number that can be represented by a five-digit decimal number. The SID is used by a network to identify itself. Each SID is globally unique and assigned to a particular operator. The SID is also usedwithin the MSC Identity and to properly route roaming call records for billing among roaming partners. A SID is allocated to a carrier by its national telecommunications authority or an appointed agent. The SID is assigned and administered from the country’s allocation of SID range. A SID range is allocated to an administrator by the International Forum on ANSI-41 Technology (IFAST). There are cases where SIDs are being used outside of the bounds of their IFAST allocation. The known SID conflicts are detailed on the IFAST web site at http://www.IFAST.org. In the United States, a SID for the cellular band (800 MHz) used to be assigned by the Federal Communications Commission (FCC). In August 2002, the FCC adopted an order[1] which transitioned the administration of SIDs to the private sector. There are six cellular SID administrators that can issue a SID in the US. USA PCS band (1850 – 1990 MHz) SID administration is performed by CIBERNET. PCS SIDs were originally assigned by CIBERNET according to the FCC auctioned PCS license areas[2], however, recently there has been consolidation of SIDs to commercial markets.Network Identification CodeThe Network Identification Number (NID) is a 16-bit binary number that can be represented by a five-digit decimal number. The use of a NID, by the mobile device, to identify a network is optional. The NID is used to subdivide the SID namespace. Each NID is unique to a particular SID. A NID is locally assigned and administered by the operator owning the SID. [1] The FCC eliminated the use of SIDs and the SID assignment process in its entirety as part of the license application as a part of the FCC Year 2000 Biennial Regulatory Review (Amendment of Part 22 of the Commission’s Rules to Modify or Eliminate Outdated Rules Affecting the Cellular Radiotelephone Service and other Commercial Mobile Radio Services, WT Docket No. 01-108, Report and Order, FCC 02-229 (released Sept. 24, 2002), the section 22.941 of the Commission Rules, 47 C.F.R. § 22.941).[2] PCS license areas, which follow the Rand McNally definition of Major Trading Areas (MTAs) and Basic Trading Areas (BTAs).



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Section 2-5



Every CDMA system is uniquely identified by the combination of:

• System Identification Code (SID)

• Network Identification Code (NID)

• Mobile Country Code

• Mobile Network Code

• Radio Frequency (Band Class or Channel)

The Market

Cellular Geographic

Service Areas

Operator A’s implementation

of the market

Operator B’s implementation

of the market

Mobile Country Code

The mobile country code (MCC) identifies the country in which the network operates. An MCC is issued by the Telecommunications Standardization Body (TSB) of the International Telecommunications Union (ITU) and is globally unique. A list of existing and valid mobile country codes can be found on the ITU web site at http://www.itu.int/itudoc/itu-t/ob-lists/icc/index.html.

Mobile Network Code

A mobile network code (MNC) identifies a particular network within a mobile country code and is thus unique within a particular MCC. While recent standards allow for an MNC of two or three digits, the majority of deployed commercial infrastructure uses a two digit MNC (irrespective of technology). In CDMA the MNC is often referred to as the IMSI_11_12. Every CDMA system broadcasts its MCC and IMSI_11_12 (MNC).

An MNC is issued by in-country administrators (a regulatory body or an appointed agent). Administrators are requested to keep the TSB informed of MNC allocations. A list of existing and valid mobile country codes can be found on the ITU web site at http://www.itu.int/ITU-T/inr/forms/mnc.html.

Home Network Identity

Every commercial, public service, mobile network can be described by a description known as the Home Network Identity (HNI). In some technologies, this HNI is referred to as the PLMN-Id (Public Land Mobile Network Identity). The HNI is comprised of a mobile country code (MCC) and a mobile network code (MNC). Since recent standards allow for an MNC of two or three digits, some administrators now allocate a six digit HNI (i.e., a 3 digit MCC and a 3 digit MNC). In the case where the majority of the deployed base of commercial infrastructure can only use a two digit MNC (again, irrespective of technology) the allocation guidelines have generally been temporarily adjusted so that only an agreed two of the allocated three digits are broadcast and that integrity is preserved. Such is the case in the USA.



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Section 2-6



Every CDMA system: • Operates on a particular

frequency or CDMA channel

The Same SID:• May be in broadcast by the

same operator in adjacent CGSAs

• The same operator’s licenses may be in the same market on different spectrum bands

Cell ACell BPCS APCS BPCS CPCS DPCS EPCS F Sid 1

Sid 1

The Radio Frequency – Band Class and ChannelEvery CDMA system operates on a particular frequency, or more specifically, a particular channel within a particular Band Class.Band Class is the term used to describe the standards segmentation of the frequency spectrum. Channel describes an allocation ofa portion of bandwidth within a Band Class, channel number only has meaning in the context of a Band Class. The bandwidth of a channel varies across Band Classes (these channel widths are not related to the actual bandwidth used by a CDMA carrier). Band classes and channels are described in the 3GPP2 document C.S0057.The Band Class can be used to further characterize a CDMA system in addition to combining the broadcast identity together with the some classification of the radio frequency on which the system is operating.Identification Attributes Applicable to PRLsThe short discussion above yields five attributes that can be used to identify a CDMA system:

System IdentificationNetwork IdentificationMobile Country CodeMobile Network CodeRadio Frequency (Band Class)

In the context of the PRL, two combinations of three of these attributes are available to be used for the purposes of system selection. The most commonly used is the set of:

System Identification Code (SID) Network Identification Code (NID)Radio Frequency (Band Class)

Later our discussions will show the capability for the PRL to describe systems in terms of the three attributes of:Mobile Country Code (MCC)Mobile Network Code (MNC or IMSI_11_12)Radio Frequency (Band Class)



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Section 2-7


What is a Preferred Roaming List (PRL)?

The PRL is:• Built by the operator • In the handset• Inaccessible to the user• A list of systems a mobile can access

The PRL:• Indicates frequencies to search • Indicates systems to select or avoid• Indicates system preferences• Speeds up acquisition• Indicates whether the roam status displays

What is a Preferred Roaming List (PRL)?

The PRL is often considered in two subtly different ways depending on an individual’s particular context:

Some see the PRL as a set of RF channels on which to search for service and the description of systems that can be found on those channels.Others look at the PRL as being a list of mobile network systems that a mobile device is allowed to access and the frequencies on which they can be found.

Both are, of course, correct. The preferred roaming list is a device resident database. It does contain an indexed list of frequencies on which to search for particular systems. The PRL contains a list of systems that a device is permitted to access, and, those that it is explicitly forbidden to access. The list of systems is known as the System Table and the list of frequencies is known as the Acquisition Table

The PRL contains information to assist the mobile station in the system selection and acquisition process. It indicates which systems the mobile station should use (preferred systems) and those which should not be used by the mobile station (negative systems). In addition to indicating which systems are preferred or negative, the PRL has information that can help to optimize the acquisition time.

The PRL is built by an operator, loaded into the mobile device, and is not accessible by the user. The full definition of the PRL is fully described in the standards—specifically the IS-683 family of standards, from revision A to revision E.

The Function of the Preferred Roaming List

The PRL assists the mobile in the acquisition and system selection process as governed by the system determination algorithms ofthe particular implementation. The PRL informs the device’s system determination function as to which systems are permitted, preferred and prohibited. The use of a PRL speeds up acquisition and provides the operator with flexibility in specifying mobilesearch behavior in both the home and roaming markets.

The operator is able to specify whether a “Roam” condition is to be indicated on the mobile’s display and in the case where the Extended Roaming Indicators (ERI) are supported, a richer set of indicators can be selected for display.

The PRL standards (at various revisions) allow for the specification of a PRL covering cdmaOne systems (IS-95), CDMA2000 (1xRTT) systems, IS-856 systems (CDMA2000 1X/IS-95 1xEV-DO), and UMTS/GSM systems.



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Section 2-8


Organization of a PRL Database

The PRL comprises :• General PRL information• An Acquisition Table• A System Table

The Acquisition Table contains:• One or more acquisition records

The Acquisition Record contains:• The RF environment type• Channel, Band, or Block information

The System Table contains:• One or more Geographical areas (GEOs)

A Geographical area contains:• One or more system records

A System Record contains:• An identity—SID, NID pairs• A link to an acquisition record• Priority in the GEO• Roaming display behavior• Prohibited Indicator

PRL Structure

The PRL comprises three major sections:

a properties set (header information) that provides general information about the PRL,an acquisition table that lists all the frequencies that the device can search, and a system table that describes the systems.

PRL Header Information (Properties)

The PRL Header information describes the properties of the whole PRL. These properties describe aspects such as its name (or identity), default behavior and the type of PRL.

Acquisition Table

The acquisition table contains acquisition records. An acquisition record provides the band and frequencies that the mobile station is to use when searching to acquire a system. Acquisition records are listed in priority order (highest priority first) in the acquisition table. The channels in the “CHAN” field of the records are also listed in the priority order.

System Table

The system table contains records describing a system. The System Table is divided into one or more distinct segments; these arecalled Geographical Areas, or GEOs. A system record belongs to a Geographical Area. A geographical region would normally be used to group a set of systems found in the same physical region. Certain other aspects of a system record only have relevance within the context of a GEO, e.g., priority. A system, in the context of the system table, is identified by its SID and NID. Each system table record has an indicator, which determines within which geographic area that a particular system belongs.

Other indicators declare whether the system is preferred (permitted) or negative (prohibited). Allowed systems can have relativepriority with respect to each other within a geographic region, effectively making some systems more preferred than others. The priority that a system has is relative to the other systems in the same GEO. The most preferred system is the most desired system and what the mobile device will always try to obtain service. There is no limit to the number of priorities that can be present within a GEO. There can be multiple systems of equal priority.



80-W0902-1 Rev C



Section 2-9


Is a PRL Always Required?

• CDMA System Selection is automatic and cannot be user directed.

• Without a PRL, a mobile can operate only in the 800 MHz band using a Primary and/or Secondary channel to access System A or System B (i.e., operating in preferred mode).

• Generally, all IS-2000 devices are manufactured with a PRL. However, a device-resident non-volatile (NV) memory parameter can sometimes be used to enable or disable the PRL.

CDMA’s Automatic System Selection

Network selection in CDMA is fully automatic. There is no capability for manual override by the user. While some devices may allow a user to influence the general behavior of selecting a system, regardless of the PRL, CDMA does not provide the user with a selectable list of available systems. For example, “Digital Only” would avoid all analog systems and “Home Only” would avoid all systems indicated as roaming.

Operating Without a PRL

Without a PRL, a mobile can only scan the standard channels of Band Class 0 and Band Class 1. The standard channels for Band Class 0 are defined in a handset’s NV-RAM. In the U.S., these are typically set to the preferred set of channels defined in IS-2000 (i.e., 283 for primary A, 384 primary B, 691 secondary A, and 777 secondary B). Band Class 1 standard channels are predefined. The mobile’s system selection behavior, in terms of choosing a preferred system, is determined by device-resident, non-volatile (NV) memory parameters (NV_SYSTEM_PRF_I, for instance).

Because PRLs have many advantages, few if any CDMA mobile devices operate without a PRL.

Disabling the PRL

Generally, all IS-2000 devices are manufactured with a PRL. However, there is often a device resident non-volatile (NV) memory parameter[2] that can be used to enable or disable the PRL. If the PRL is disabled, then the mobile device uses something called the default roaming list concept for operation on 800 MHz cellular networks and 1900 MHz PCS networks, where the device will scan only the predefined preferred channels for each Band Class. The operation without a PRL is not common.

[1] ‘NV_SYSTEM_PREF_I’=’Standard’ and ‘NV_PREF_MODE_I’ = ‘NV_MODE_AUTOMATIC’

[2] ‘NV_PRL_ENABLED_I’



80-W0902-1 Rev C



Section 2-10


Where is the PRL and How Does it Get There?

• The PRL can be stored in either of the following:– NV-RAM – Removable User Identity Module (RUIM)

• An initial or default PRL would be loaded into the phone or RUIM prior to distribution.

• A new PRL can be loaded into the handset:– At a customer service center, using service

programming tools

– Over the air using OTASP (Over the Air Service Provisioning – see IS-683)

Although the PRL is defined in the OTASP specification, OTASP is not required to use PRLs.

OTASP facilitates ease of updates once handsets are in customers’ hands and as new roaming partners are added.

Notes



80-W0902-1 Rev C



Section 2-11


CDMA RAN (IS-683)CDMA RAN (IS-683)

Updating the PRL Over the Air

Terminology• Over The Air Service Provisioning (OTASP)• Over the Air Parameter Administration (OTAPA) –

network initiated• Over The Air Function (OTAF)• System Selection for Preferred Roaming (SSPR)

(i.e., PRL) download

Standards• IS-683 describes the MS to BTS interaction (and

defines PRL)• IS-725 describes the network interactions (ANSI-41)

OTA platform• Maintains multiple PRLs (vendor specific, e.g., 256)

Process• User dials OTA feature code (*ACT) • Selects PRL update at VRU• CSC selects right PRL• OTA platform downloads PRL (user hears music)• Handset resets on completion

BTSBSC

ANSI-41 Core Network (IS725)

Billing Customer Service System

OTA Platform

AuC

HLR

MSC

PSTN

Updating the PRL Over the Air

OTASP is the term used most often to refer to how a PRL can be downloaded over the air to a mobile device. Some terminology clarification may be useful here:

OTASP (Over the Air Service Provisioning) is generally understood to mean service provisioning activities that are initiated by the user.

OTAPA (Over the Air Parameter Administration) is generally understood to mean service provisioning activities that are initiated by the network.

OTAF (Over The Air Function) is the language used in the standards to describe the functionality required to deliver the ability of OTASP or OTAPA—without specifying it to be one or multiple physical systems.

The OTA platform is the actual system that operators purchase to deliver the OTAF. It is this system that maintains the multiple PRLs that have been built by the operator and that are available for download. The number of PRL variations that an OTA Platform can store is vendor specific. The PRL that a particular customer should get would be configured by the operator and could depend on various factors, including device type and subscribed service plan.

SSPR (System Selection for Preferred Roaming) is the standards language for PRL.

CSC (Customer Service Center) is the call center, or automated voice response unit (AVRU), to which a user is connected. The CSC determines what type of service programming is to be performed. SSPR, or PRL download, is only one of the capabilitiesthat are available under OTASP.



80-W0902-1 Rev C


Which Standards Apply to PRL Download Over the Air?

The format for the PRL is actually contained in the standard that describes OTASP. There are two standards that cover OTASP:

IS-683 describes the MS to BTS interaction, specifically, defining the OTASP protocols and the messages that can be sent over the air encapsulated in the CDMA Data Burst Message. This includes the definition of the PRL.

IS-725 describes the core network interactions between the OTA Platform, the MSC, the CSC, and the HLR as appropriate.

There are two ways in which the over the air download can happen, one that the user initiates and one that the network initiates, i.e., OTASP and OTAPA respectively.

User Initiated PRL Download

This is the more common technique, and requires that the user take the initial action by making a call using the activation feature code; *ACT or *228. Users can dial the OTA feature code (*ACT) and select PRL update at Voice Response Unit (VRU) prompt. The OTA Platform selects the appropriate PRL to send to the device based on factors including handset, service plan, etc. OTA platform downloads PRL to the user over its IS-725 data connection to the MSC and then over the air using the IS-683 protocol. The VRU may play music during this time. The handset resets on completion of the PRL download.

Network Initiated PRL Download

This is where the network initiates an OTAPA session with the mobile device and performs the PRL download without user intervention. This requires that both the network and the device are OTAPA capable and that the OTAPA capability is not disabled. A Subscriber Parameter Administration Security Mechanism (SPASM) exists to ensure that only authorized entities can download to the device. When the device parameters are protected, the mobile device requests a ‘signature’ from the network and, at the same time, calculates a signature itself. The OTA system, upon receiving the device’s challenge, will request the HLR to obtain an authentication signature (from the Authentication Center). The OTA system forwards the signature to the MS and only when the MS reports that the two signatures match can the PRL download proceed.

Update of PRL Outside of Home Network

The standards do not preclude the ability of connecting to another service provider’s OTA system; however, this requires cooperation and configuration by both operators to re-direct to the home network CSC and/or OTA system and allow roamers home network OTA system to communicate with partner network’s serving MSC. Of course there is the obvious problem that the PRL must have permitted access to the serving system in order to be able to make the call to the CSC at all. Assuming the PRL contains sufficient information to access the serving system, the only reason to perform an update remotely would be if there was a change in the systems or preferences for that market or if “fuller detail” for the market was needed. Each of these situations would be part of any PRL management strategy.

Remote PRL download is something that partner operators would have to individually consider and plan to accommodate. The serving network would need to route to the appropriate CSC and OTA platform.



80-W0902-1 Rev C



Section 2-13


What Does a PRL Look Like?

What you may see in an Editor:

PRL Properties

Acquisition Table

System Table

Anatomy of the PRL from Editor

The PRL has three major components, the header, the system table, and the acquisition table. In this section we look at the PRL as you might see it in the PRL editor and then relate that to the standard definitions of the PRL data structures. In each instance, a discussion follows to explain the meaning.



80-W0902-1 Rev C



Section 2-14


Understanding the Properties of a PRL

The actual record being described:

16PR_LIST_CRC

0 to 7 (as needed)RESERVED

variableSYS_TABLE

variableACQ_TABLE

14NUM_SYS_RECS

9NUM_ACQ_RECS

8DEF_ROAM_IND

1PREF_ONLY

16PR_LIST_ID

PR_LIST_SIZE

Field

16

Length (bits)

TRUE -Only use non-negative systems in the PRL System Table.

‘1’

‘0’PREF_ONLY

FALSE - Use only on-negative system from the System Table AND systems that are not described in the System Table as either

Description

The Label or version assigned to the PRL

If PREF_ONLY is ‘FALSE’ then this is the roaming indicator to use for non-PRL systems

PRL PropertiesEditor View:

PRL Header Information – Editor View

The PRL Header information describes the properties of the whole PRL. These properties describe aspects such as its name (or identity), default behavior, and the type of PRL.

What It Describes and What It Means

The information in the header as defined by the standard is shown. Only the shaded portions are displayed in the editor. The rest (the unshaded part of the table) really describes the size, packaging, and housekeeping overhead that we can rely on tools, such as a PRL editor, to add based on the dimensions of the final PRL.

The Roaming List Type in this particular editor view refers to which particular standards revision describes this PRL; this one is IS-683B. This would be seen generally in a PRL editor that supports multiple versions of IS-683. To understand what this editor view is actually describing, let’s look at what the standard says is in the header and link these two views. Preferred Roaming List ID is what the standard calls PR_LIST_ID. It is a number between 0 and 65,535 that can be used to identify and version control a PRL. Preferred Only in the standards is called PREF_ONLY and indicates if only systems in the PRL are to be used. If preferred only is not checked (i.e., set to 0), then this is what is sometimes called a “permissive PRL,” meaning systems not described in the PRL can be used. This is something worth noting as it can be the cause of unexpected behavior. Use of this flag does not mean that the PRL is ignored; rather it means that service can be provided by any system that is not described in the PRL and that the system selection process will continue to search for a more preferred system as indicated by the PRL. This can be useful to ensure coverage where it is present and accessible to the user but may not have been included in the PRL (provided that the user can register or the system rejects an invalid registration).Default Roaming Indicator in the standards is DEF_ROAM_IND. It is the roaming indication used for systems that are not described in the PRL and applies when Preferred Only is not checked. The values that can be used in this field are the same as those used in the System Record of the System Table, which is described later.



80-W0902-1 Rev C



Section 2-15


Acquisition Table

Editor View:

683-A Acquisition records1. Cellular Analog2. Cellular CDMA (Standard Channels)3. Cellular CDMA (Custom Channels)4. Cellular – CDMA Preferred5. PCS CDMA using Blocks6. PCS CDMA using Channels

683-B• JTACS CDMA (Standard Channels)• JTACS CDMA (Custom Channels)• 2 Ghz Band (Channel)

683-C• CDMA Generic

– 800 MHz-Cellular, PCS, TACS, JTACS, Korean-PCS, NMT-450, IMT-2000, 700-MHz-Cellular.

• HDR Generic

Acquisition Table

The acquisition table defines, in priority order, the radio environment (frequencies) that are to be searched for service. The acquisition table consists of a minimum of one and up to 512 acquisition records. Each acquisition record is of a specific type and describes one or a set of frequencies to search.

The priority ordering of the records in the acquisition table is derived from their sequential order and is generally used by the system selection process to construct scan lists reflecting the order in which frequencies appear in the acquisition table. Also, where a set of frequencies are listed within a record of the acquisition table, the order in which they are listed is often an implied ordering for scan lists.

An example of what an acquisition table might look like in a PRL editor is shown.

The type of acquisition records that can be defined in a PRL are dependent on the revision of the standard in use for that particular PRL. The particular types as they apply to revisions A through C are listed above.



80-W0902-1 Rev C



Section 2-16


Cellular Analog Acquisition Record


The actual record that is being described:

What it means to the mobile:• Search for 800 MHz AMPS Cellular Systems on

– A Band only – B Band only– Both A and B bands

2A_BACQ_TYPE

Acquisition Record Field

5

Length (bits)

Both A & B‘11’Reserved‘10’System B‘01’

‘00’A_B Selection Type

System ADescription

‘0001’ = 1

Cellular Analog Acquisition Record

This record is used to instruct the mobile device to look for AMPS Cellular service in Band Class 0 (the 800 MHz cellular) frequencies.

The figure shows the editor view of the analog cellular acquisition record and the table shows the actual field names and lengths described in the standard.

Acquisition Type

The Cellular Analog acquisition record has an “ACQ_TYPE” value of “1” (binary 0001). An editor will generally show a meaningful descriptive term for this, as in the example shown where it is shown as “Analog Cellular.”

Exactly where the device should search for cellular analog service is defined by the next field.

Systems

This is the band within the 800 MHz cellular frequencies. This system is called the “A_B” field in the standards and can take one of three legal values. These values allow the device to be directed to look for analog systems in:

A Band only B Band only Both A and B bands



80-W0902-1 Rev C



Section 2-17


Cellular CDMA (Standard Channels) Acquisition Record


What it means:• Look for 800 MHz CDMA ONLY (Cellular) Systems on:

– A Band Primary channel (283) – B Band Both Primary and Secondary Channels (384 and 777)– Both A and B bands and Both Primary and Secondary channels (283, 691, 384, 777)

2PRI_SEC

2A_B

ACQ_TYPE


5

Length (bits)



System ADescription

Primary or Secondary CDMA Channels

‘11’

Secondary CDMA Channel (691,777)‘10’Primary CDMA Channel (283, 384)‘01’

‘00’PRI_SEC

ReservedDescription

The actual record that is being described: ‘0010’ = 2

Cellular CDMA (Standard Channels) Acquisition Record

This record is used to instruct the mobile device to look for CDMA service, and CDMA only, in Band Class 0. More particularly, only on the standard channels in a particular band of Band Class 0 (the 800 MHz cellular frequencies).

The figure shows one particular editor view of the CDMA cellular, standard channels acquisition record. The table shows the actual field names and lengths described in the standard.

Acquisition Type

– An acquisition record describing CDMA cellular standard channel systems has an “ACQ_TYPE”value of “2” (binary 0010).

– An editor will probably not display this actual value and would generally use a more descriptive name, as in the example, where it is shown as “CDMA Cellular (Standard).

Systems

– This describes the band within the 800 MHz cellular frequencies. This system field is known as the “A_B” field in the standards and can take one of three legal values. These values allow the device to be directed to look for CDMA systems in A Band only, B Band only or both A and B bands. The table shows the actual values as represented in the standard and their meaning.

Channel

– For this type of record the channel as shown in the editor example is an indicator to the mobile device if it is to look on the standard primary channel or the standard secondary channel or both the primary and secondary.

– This channel editor field is known as the “PRI_SEC” field in the standards and can take one of three legal values. The table shows the actual values as represented in the standard and their meaning.



80-W0902-1 Rev C



Section 2-18


What are Cellular CDMA Standard Channels?

• For CDMA Standard acquisition records, the actual CDMA channels come from the device non-volatile RAM.– NV_PCDMACH_I - primary-A and primary-B – NV_SCDMACH_I -secondary-A and secondary-B

• Specified by the operator; generally specified in the PRI.

• In the United States, the preferred set of channels that are defined in IS-2000: – 283 primary A, 384 primary B– 691 secondary A, 777 secondary B

• An operator with different primary channels in the home market than in the roaming market should be aware of the effect of using CDMA Standard acquisition type.

CDMA Standard Channels

A question that often arises when service providers use the “cellular CDMA standard channels”acquisition record type in the acquisition table is “how does the mobile know what the CDMA channels are?”

For Band Class 0 only, the actual CDMA channels come from NV-RAM[1] and, as may have already been deduced from the tables above, there are four such channels, namely, primary-A, primary-B, secondary-A, and secondary-B. These channels are programmed into NV by the operator (or specified by the operator to the manufacturer in the Product Release Information (PRI)).

In the United States they are typically set to the preferred set of channels defined in IS-2000, as shown above.

An operator that has primary and/or secondary channels that are different in the home market than in the roaming market and uses either “Cellular CDMA Standard Channel” or “CDMA Preferred” (see later) in their PRL must be aware of the potential effects in the roaming markets.

[1] NV_PCDMACH_I - primary-A and primary-B, NV_SCDMACH_I -secondary-A and secondary-B.



80-W0902-1 Rev C



Section 2-19


Cellular CDMA (Custom Channels) Acquisition Record


What it means:• Look for 800 MHz CDMA ONLY (Cellular) Systems on

– The list of channels provided– Scan the channels in the order in which they are listed

11CHAN

NUM_CHAN occurrences of

5NUM_CHANS

ACQ_TYPE


5

Length (bits)

1201… 16001041..1199801..1039

1..799CHAN

List of CDMA Channels to search

Description

The actual record that is being described:‘0010’ = 3

Cellular CDMA (Custom Channels) Acquisition Record

This acquisition record is used to search for CDMA service in Band Class 0 (800MHz Cellular frequency band) on a list of (up to 31) specific channels. Furthermore, it means that channels are searched in the order in which they are listed.

Editor View

Above shows one particular editor view of the CDMA cellular, custom channels acquisition record. The table shows the actual field names and lengths described in the standard.

Acquisition Type– An acquisition record describing custom channels in the cellular band (Band Class 0) has an

“ACQ_TYPE” value of “3” (binary 0011). An editor my not display this value and instead use a descriptive term for this, as in the example, where it is shown as “CDMA Cellular (Custom).”

Channels– This describes the channels within the 800 MHz cellular bands. This channel field is known

as the “CHAN” field in the standards. There can be from 1 to 31 channels specified in one acquisition record. Table 4-10 shows the channel values that can be used in the Cellular CDMA Custom Channels acquisition record.

– The standards describe the NUM_CHANS field also which indicates how many channels are in this record (1 to 31). Normally, if an editor or some equivalent tool is used then the tool would calculate and maintain this as part of its housekeeping.



80-W0902-1 Rev C



Section 2-20



What it means to the mobile:• Search for 800 MHz CDMA Systems (Standard Channels) in the Bands specified.• IF a CDMA System is found use that.• IF NO CDMA SYSTEM is found, search for AMPS Cellular System.

This may be done before moving to any other acquisition records (Scan List).Without careful design, inadvertent selection of Analog over CDMA may occur.

• If the aim is to search for all CDMA systems first, the PRL should be structured that way.

Cellular CDMA Preferred Acquisition Record


2A_B

ACQ_TYPE


5

Length (bits)



System ADescription

‘0001’ = 4

Cellular CDMA Preferred Acquisition Record

This record is used to instruct the mobile device to search, in Band Class 0, for CDMA service first (on the standard channels in a particular band), and, if no CDMA service is found, look for AMPS Cellular service in the same band. This is generally done before moving to any other band/channel.

If the intention is to select a CDMA system over an Analog system on a particular channel, then this is the record to use. If the intention is to find all CDMA systems on all (or any combination of) standard channels before selecting any analog system, then the acquisition table should be explicitly structured that way. Without careful design, inadvertent selection of Analog over CDMA may occur. For example, use of CDMA preferred acquisition records can result in the AMPS service of a higher priority system being selected over the CDMA service of a lower priority system. This may or may not be the intention of the PRL designer.

The figure shows one particular editor’s view of the CDMA cellular, standard channels acquisition record. The table shows the actual field names and lengths described in the standard.

Acquisition Type– An acquisition record describing custom channels in the cellular band (Band Class 0) has an

“ACQ_TYPE” value of “4” (binary 0100). Editors often display a more human readable form, as in the example where it is shown as “CDMA Cellular (Preferred).”

Systems– The system fields shown in the editor example describes the band within the 800 MHz cellular

frequencies. These values allow the device to be directed to look for CDMA systems in A Band only, B Band only, or both A and B bands This system field is known as the “A_B” field in the standards and can take one of three legal values.



80-W0902-1 Rev C



Section 2-21


PCS CDMA Blocks and Channels

Blocks• Scanning the preferred list of

channels in the Blocks specified.

• Scan the channels sequentially in the block order specified.

Channels• The list of channels provided.• Scan the channels in the order

in which they are listed.

825,850,875F725,750,775E325,350,375D

C

BA

Block

925,950,975,1000,1025,1050,1075,1100,1125,1150,1175

425,450,475,500,525,550,575,600,625.650,67525,50,75,100,125,150,175,200,225,250,275

Preferred Channels

25-1175

CHANPCS CDMA Channel Number as defined in 6.1.1.1 of

TIA/EIA 95-B.Priority is based on position in the CHAN list. Some of

these channels are ‘conditionally valid”

Description

CDMA PCS Blocks

Using the “by blocks” acquisition record infers that all of the preferred channels are placed in the scan list to be searched for CDMA service. The preferred channels for CDMA in the PCS blocks are shown above. These are defined in 3GPP2/C.0057

CDMA PCS Preferred Channels

Using the “by channels” acquisition record infers that all of the listed channels are placed in the scan list, in the order that they appear, to be searched for CDMA service. The range of channels for CDMA in the PCS blocks are shown above.



80-W0902-1 Rev C



Section 2-22


PCS CDMA (Using Blocks) Acquisition Record


What it means:• Look for 1900 MHz CDMA (PCS) Systems ONLY by:

– Scanning the preferred list of channels in the Blocks specified– Normally channels would be scanned sequentially in the block order specified.

3BLOCK

NUM_BLOCKS occurrences of

3NUM_BLOCKS

ACQ_TYPE


5

Length (bits)

Any Block‘111’Reserved‘110’

825,850,875F‘101’725,750,775E‘100’325,350,375D‘011’

CBA

Desc.

925,950,975,1000,1025,1050,1075,1100,1125,1150,1175‘010’425,450,475,500,525,550,575,600,625.650,675‘001’

‘000’Block

25,50,75,100,125,150,175,200,225,250,275Preferred Channels


‘0010’ = 5

PCS CDMA (Using Blocks) Acquisition Record

This record is used to instruct the mobile device to look for CDMA service on the preferred CDMA channels in a particular block of Band Class 1 (the 1900 MHz PCS frequencies).

Up to eight blocks can be specified (although tools such as editors often limit this to 6 since there are only six defined PCS blocks). The order in which the blocks are listed is generally the order that they will be searched. The figure shows one particular editor view of the CDMA PCS, using Blocks acquisition record. The table shows the actual field names and lengths described in the standard.

Acquisition Type– An acquisition record describing blocks in the PCS band (Band Class 1) has an

“ACQ_TYPE” value of “5” (binary 0101) and has the structure as shown. Typically, editors would not show the actual type value. The figure shows a possible editor display form of this field as “CDMA PCS (blocks).”

Block– For this type of record the block (as shown in the editor example) is an indicator to

the mobile device as to which PCS block or blocks to search for CDMA service.– This Block n editor field is known as the “BLOCK” field also in the standards and

can take one of seven legal values. The table shows the actual values as represented in the standard and their meaning.



80-W0902-1 Rev C



Section 2-23


PCS CDMA (Using Channels) Acquisition Record


What it means:• Look for 1900 MHz CDMA (PCS) Systems ONLY on:

– The list of channels provided– Scan the channels in the order in which they are listed

11CHAN

NUM_CHAN occurrences of

5NUM_CHANS

ACQ_TYPE


5

Length (bits)

25-1175

CHAN

PCS CDMA Channel Number as defined in 6.1.1.1 of TIA/EIA 95-B.

Priority is based on position in the CHAN list. Some of these channels are ‘conditionally

valid”

Description


‘0010’ = 6

PCS CDMA (Using Channels) Acquisition RecordThis record is used to instruct the mobile device to look for CDMA service on the channels listed in Band Class 1 (1900 MHz PCS frequencies). Up to 31 channels can be specified. The order in which the channels are listed is generally the order that they will be searched. One particular editor view of the CDMA PCS, using Channels acquisition record, is shown. The table shows the actual field names and lengths described in the standard.

Acquisition Type– An editor will generally show a meaningful descriptive term for the acquisition type,

as in the example, where it is shown as “CDMA PCS (Channel);” however, in the standards this is described by the “ACQ_TYPE” field having the actual value “6” to represent CDMA PCS (using Channels).

Channels– This channel fields in the editor describe the channels to be searched within the 1900

MHz PCS bands. This channel field is known as the “CHAN” field in the standards. There can be from 1 to 31 channels specified in one acquisition record. The table above shows the channel values that can be used in the PCS CDMA using Channels acquisition record.

– The standards describe the NUM_CHANS field, which also indicates how many channels are in this record (1 to 31). Normally, if an editor or some equivalent tool is used then the tool would calculate and maintain this as part of its housekeeping.



80-W0902-1 Rev C



Section 2-24


System Table

• Contains the descriptions of all the systems that are: – Permitted to provide service – Prohibited from providing service

• Between one and 16,383 system records (subject to physical storage limits).• In the context of the PRL a system is identified by a broadcast identity:

– System Identification, Network Identification – Mobile Country Code, Mobile Network Code– The frequency band on which the system was found

• System records are explicitly grouped in Geographical Areas.• Permitted (or preferred) systems in can be assigned a priority.

System Table

The system table contains the descriptions of all the systems permitted to provide service or prohibited from providing service.Each system is described in a system record. The system table consists of a minimum of one and up to 16,383 system records; the actual number may be subject to the physical amount of storage available on the device. Each system record describes one or more CDMA systems that are permitted or prohibited.

In the context of the PRL a system is identified by a broadcast identity ([System Identification, Network Identification] or [Mobile Country Code, Mobile Network Code]) and the frequency band on which the system was found. System records are explicitly grouped together. Groups of systems are termed Geographical Areas. Permitted (or preferred) systems can be assigned apriority. Priority ordering in the system table is explicit, unlike the implicit priority ordering of the records in the acquisition table. Priority ordering only has scope and relevance within the Geographical Area groups.

System Type and System Record Type

In defining system records, a PRL editor often allows the specification of a system type. The system type in the PRL editor is in descriptive form (“1X/IS-95,” “HRPD/IS-856” for 1xEV-DO, etc.). The system type would generally translate to a system record type.

One thing to be aware of here is that system record types did not exist prior to IS-683-C when a new form of system record was introduced, known as the extended system record format. The extended system record format enabled the PRL description of systems with different sets of attributes than those used to describe the basic 1X/IS-95 systems. The first such system to be defined as a new type was the high rate packet data system (1xEV-DO). Prior to this, all system records were of the same type, which is referred to in this document as the Basic System Record. Often when people talk of the extended PRL, they are referringto the extended record formats that are offered in IS-683C. With the increasing presence of 1xEV-DO systems the use of extended system record format is becoming more common.

With the new extended system record format it became possible to identify a type of system record as an explicit field. A basic system record of IS-683 A and B can be expressed in a the extended system record format using a Type=0. A stored variable in the mobile device indicates which type of PRL that the device can support. This variable is called SSPR_P_REV. An SSPR_P_REV value of “1” indicates that the only the basic record formats can be supported. An SSPR_P_REV of “3” indicates support of an Extended Preferred Roaming List containing Extended System Records.



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Section 2-25


System Table Record

Actual System Table Record

0 OR 8ROAM_IND

9ACQ_INDEX

0 OR 1PRI

1GEO

1PREF_NEG

0 OR 16NID

2NID_INCL

SID

System Record Field

15

Length (bits)

PREFERRED – Permitted system‘1’‘0’

PREF_NEGNEGATIVE - Prohibited system

Description

0 TO 327670 SIGNIFIES WILDCARD = ANY SID

SAME geographic area as the previous entry‘1’‘0’

GEONEW Geographic area relative to previous entry

Description

MORE preferred than the FOLLOWING Entry‘1’‘0’PRI

SAME Priority as the FOLLOWING EntryDescription

Reserved’11’NID not included, assume 0’10’NID included’01’

’00’NID_INCL

NID not included assume 65535Description

0 TO 6553565535 SIGNIFIES WILDCARD = ANY NID

Basic 1X/IS-95 System Record

The systems that are to be preferred or barred are described in a system record of the system table. An editor view of the system table is shown. Each line is a system record. The specific fields of a system record are shown.

The following sections describe each element of the PRL’s system record.

SID – System Identification. This field is set to the SID broadcast by the system that this record represents. The SID is a 15 bit binary field that can be represented by a 5 digit decimal number between 0 and 32,767. A non-zero value for SID is a specific broadcast SID. The value of “0” serves as a SID wildcard and generally describes any other SID that is not specified in any other system record. A specific or wild card SID still means that the system is on a frequency described by the acquisition record associated with it by the ACQ_INDEX.

NID – Network Identification. The NID is an optional field. Its presence is indicated by the use of the NID_INCL field. A NID_INCL value equal to ‘01’ indicates that the NID is included and is set to the NID of the network associated with this record; otherwise this field is omitted. The maximum NID value (65535) denotes any NID (i.e., serves as a NID wildcard). Not including the NID field is equivalent to including it and setting it to ‘1111111111111111.’ The value ‘0 denotes a NID of the public system.

Geography

The strategy of system table segmentation is implemented by using the GEO field. If this is the first system record, this field is set to ‘0.’ If this is not the first system record, then this field is set as follows: if the system associated with this record is in the same geographical region as the system associated with the previous system record, this field is set to ‘1’; otherwise, this field is set to ‘0.’



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In an editor this is normally seen as “SAME” and “NEW” as opposed to “1” and “0." The important aspect of the GEO flag is that it is a relative description with respect to the previous system table entry; i.e., a GEO is either the “SAME” as the previous or it is not the same as the previous in which case it is “NEW”—another GEO.

Negative/Preferred

This field is set to ‘1’ if the mobile station is allowed to operate on the system associated with this record. This field is set to ‘0’ if the mobile station is not allowed to operate on the system associated with this record.

Priority

Only a preferred system can have priority, negative systems are all equally disliked and equally prohibited, so if the PREF_NEG field of this system record is equal to ‘0’ then this field is omitted. Preferred systems on the other hand can be declared in preference order, and indeed systems can share the same level of preference. The declaration of preference is the implicit instruction to the handset’s system selection function that it must try and always reach the most-preferred system.

The priority field is a relative description with respect to the next system table entry; i.e., priority is either the “SAME” as the next or it is “MORE” than the next record. Since priority only has relevance within the context of a GEO, the last preferred system record in a GEO, or if the next record describes a prohibited system, this field has no meaning and is set to ‘0.’

If the system associated with this system record is more desirable than the system associated with the next system record, this field is set to ‘1.’ If the system described by this system record is as desirable as the next described system, i.e., it has the same priority, then this field is set to ‘0.’

The important thing to remember here is that unlike the GEO, the priority setting of a system record affects the subsequent record.

Acquisition Index

This field is set to the index of the acquisition record that specifies the acquisition parameters for the system associated with this record. Note: The index of the nth acquisition record is n-1. For example, the index of the first acquisition record in ACQ_TABLE is 0, and the index for the fourth acquisition record is 3.

Roam Indicator

Only a preferred (or available) system will display a roaming indicator. Negative systems will not be able to provide service, hence, for those systems, this field is omitted.



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Section 2-27


Size Matters

Acquisition Record Type Min Size

Bits

Bits per extra Element

Max num extra elements

Max Size

(bits)

Analog 6 - - 6

CDMA Standard 8 - - 8

CDMA Preferred 8 - - 8

CDMA Custom 20 11 31 361

PCS (Block) 10 3 5 25

PCS (Custom) 20 11 31 361

CDMA Generic 25 16 15 265

SID

NID_

INCL

NID

PREF

_NEG

GEO

PRI

ACQ_

INDE

X

ROAM

_IND

Size (bits)System Record Type

With NID

15 2 16 1 1 1 9 8 53

Preferred System 37

Negative System

28

Preferred System 53

Negative System

44

0.000.501.001.502.002.503.003.504.004.505.00

1 15 50 150

300

450

600

900

Number of SIDs

Sys

tem

Tab

le S

ize(

KB)

Size of the PRL – System Table Records

The upper table above shows the sizes of different types of system records (i.e., negative and preferred systems) and how they vary based on having a NID as part of the record or not. The system table is often where the headaches come by trying to get a large number of records in to a small space. The average system record (with no NID) costs 37 bits. However, as some carriers have in excess of 200 SIDs (200 SIDs = 7400 bits), then it becomes clear that adding roaming partners can become an issue.

The graph shows a representation of the size of a system table required to hold preferred system records based on no NID being included (overhead has been ignored in this example).

Acquisition Table Record Sizes

The acquisition table, in general, is not where the real estate battle is lost or won on PRLs. As is shown in the table above, it is possible to have some fairly large records in the acquisition table.

An interesting note here is that using PCS custom records can be much more expensive than using PCS by Block records, e.g., using PCS Custom to identify 5 of the 11 Block A channels costs 75 bits whereas including all channels in block A costs only 10 bits in its own record.

While avoiding unused channels may have been more important in early implementations of devices; they are generally able to scan much faster today so the efficiencies may not be as real.



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Section 2-28


Introduction to PRL – Section Review

1. What information is used to uniquely identify each system?

2. How are systems defined in the PRL?

3. How are systems grouped together in the system table?

4. What information is contained in a system record?

5. What is the purpose of the acquisition table?

6. What are three ways information is prioritized in the PRL?

Review1. Systems are identified using SID/NID (enhanced PRLs may also use MCC/MNC as described later).2. Systems are defined using system records in the system table.3. Systems are logically grouped together using GEOs (Geographic Areas) in the PRL.4. Information contained in a system record includes:

System ID (SID/NID, MCC/MNC)System typeSystem priority within the GEOWhether the system is Preferred or NegativeRoaming indicatorIndex to an acquisition record

5. The acquisition table defines candidate frequencies/channels that should be scanned, and in what order. By identifying only channels that should be scanned, rather than all possible channels, acquisition time is improved.

6. Each of the following may be prioritized in the PRL:System records within a GEO (explicitly via the priority field in the system record)Acquisition records within the acquisition table (implicitly prioritized—top to bottom)Channels within the acquisition record (implicitly prioritized—left to right)



80-W0902-1 Rev C


7. Yes, a device may operate without a PRL, but only on the standard channels of Band Classes 0 and 1. The standard channels for Band Class 0 are defined in a handset’s NV-RAM. In the U.S., these are typically set to the preferred set of channels defined in IS-2000 (i.e., 283 for primary A, 384 primary B, 691 secondary A, and 777 secondary B). Band class 1 standard channels are predefined.

8. The PRL resides either in NV-RAM (non RUIM-equipped devices) or on the RUIM.

9. PRLs are defined in the OTASP specification (IS-683).

10. The PRL in a device may be updated:

Using provisioning equipment at a customer service center

Over the air using OTASP (i.e., user dials an OTASP feature code such as *228)

Over the air using OTAPA (i.e., network initiated)

11. PRLs may operate in closed/restrictive mode (i.e., Preferred_Only = True) or open/permissive mode (Preferred_Only = False). Closed PRLs will only acquire systems defined in the system table, while open PRLs may acquire any available system if none of the systems in the systems table are found.

12. Acquisition records can define which CDMA PCS channels to scan by either:

Using a PCS CDMA using Blocks record type and listing blocks of channels. Using this method, all channel numbers associated with each block that is listed will be placed in the scan list. The preferred channels of PCS CDMA blocks are defined in 3GPP2 C.S0057.

Using a PCS CDMA using Channels record type and listing each channel number. Using this method, each channel number to be placed in the scan list must be explicitly listed in the acquisition record.


Section 2-29


Introduction to PRL – Section Review (continued)

7. Can a device operate without a PRL?

8. Where does the PRL reside on a device?

9. What specification defines the PRL?

10. How can the PRL in a device be updated?

11. What are the two modes in which a PRL can operate?

12. What are two ways an acquisition record can define which CDMA PCS channels to scan?



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Comments/Notes


PRL Technical WorkshopSection 3: How the PRL is Used

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Section 3-1


Section 3:How the PRL is Used

3SECTION

How the PRL is Used

Notes



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Section 3-2



Explain System Determination.Describe other factors that affect system selection. Explain Scanning, Scan Lists and the PRL. Describe the relationship between System Selection and the PRL.Describe what is meant by Unusable Systems.Describe what happens when there is no selectable system.

Notes



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Section 3-3


System Determination

System Determination attempts to:• Identify the best system upon which to operate.• Acquire the best system as quickly as possible.

System Determination will: • Try to acquire a specific system, or, • Stay and operate on the currently acquired system, or,• Enter power save mode.

System Determination uses:• Static, programmable information such as PRL and phone

settings• Dynamic information such as the system ID broadcast by

available CDMA systems, the RF conditions and protocols in use on available CDMA systems

• User activity

System Determination has two distinct stages:• System scanning to find a system, and then, • Applying system selection criteria to the system that has been

found.Although very closely coupled, for the purposes of explanation each stage will be described separately.

System DeterminationSystem selection is the process the device uses to attempt to:

Identify the best system for a given mobile device to operate based on the device configuration and the conditions at the location.Acquire the best system as quickly as possible.

For a given set of input stimuli the output of any CDMA System Determination (SD) is: Try to acquire a specific system Stay and operate on the currently acquired systemEnter power save mode

SD uses the information in various external factors to achieve this; these factors being:Static, programmable information such as a list of preferred and forbidden systems, a list of radio access technologies Dynamic information such as the system ID broadcast by available CDMA systems, the RF conditions and protocols in use on available CDMA systemsUser activity

Performing these tasks can be complicated by the need to support multiple radio access technologies, in a single device, to enable coexistence of technologies such as AMPS or GSM together with CDMA. Roaming agreements between operators can lead to complexity in the preference order of systems in the PRL. Often, operators have their own specific system selection requirements; which can evolve with the technology and their networks. Operator specific requirements arise for a number of reasons (to overcome network limitations, to support new features, to enforce a desired behavior) but the result is that there are various forms of system determination in deployed handsets. Any description here is a general guideline.For devices using the Preferred Roaming List, the PRL provides the data upon which system determination operates. SD can be understood to have two distinct stages:

System scanning to find a system, and then, Applying system selection criteria to the system that has been found.

Although in reality the two functions are very closely coupled, for the purposes of explanation, each will be described separately.



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Section 3-4


System Preferences

If present, preference settings can affect system determination operation:

• Mode preference – For example, CDMA-only, GSM-only, automatic

• Band preference – Desired bands

• Roaming preference – Desired roaming value (e.g., home-only)

May not be user-accessible in commercial devices.

Phone Settings Can Affect System Determination

There are mobile devise settings that, if present, can affect system determination operation. These settings may not be user-accessible in commercial devices. The default values of these settings would be determined by the operators Product Release Information (PRI) provided to the mobile device manufacturer.

Mode Preference – Used to identify the type of network the device is configured to access. This preference setting can restrict the mobile device to CDMA service only or allow it to select any network automatically (i.e., including analog) based on the rules defined in the PRL. Typical values for this parameter would be CDMA Only or Automatic. If this preference setting is set to “CDMA only,” it would over-ride the PRL and cause all analog systems to be ignored.

Band Preference – Configures the device to which frequencies (in terms of Band Class) it may search for service. This preference setting specifies the band preference for the phone and may have typical settings such as Band Class 0 (Cellular), Band Class 1 (PCS) or Any Band Class. If this preference is set to, for example, “PCS only,” then this would over-ride the PRL and render all other systems in other bands inaccessible. This may be user selectable or be determined by the capabilities of the device; e.g., some devices may only support a single Band Class.

Roaming Preference – A setting, often user accessible, that specifies the roaming preference for the mobile device. Possible settings may be Home Only, Roam Anywhere. This setting can restrict the mobile device to systems indicated as “Home Only,” which would over-ride selection of any “roaming” system in the PRL. The “Roam Anywhere” equivalent setting would not introduce any further restriction on the PRL.



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Section 3-5


System Preferences (continued)

Other settings that affect System Selection:• Home SID/NID

– A list, stored in the device – One or more Home (non-roaming) SID/NID pairs– Device is roaming if not operating on one of these HOME

SID/NID pair.

• CDMA SID/NID Lockout List– A list, stored in the device – Up to 10 entries – Service is not allowed on these systems

May not be user-accessible in commercial devices.

Phone Settings can affect System Determination

There are mobile devise settings that, if present, can affect system determination operation. These settings may not be user-accessible in commercial devices. The default values of these settings would be determined by the operators Product Release Information (PRI) provided to the mobile device manufacturer.

Home SID/NID List – Some mobile devices have the capability to store a list of system description (SID/NID) that are regarded as ‘Home Systems.’ A system defined in this list is defined to be non-roaming and, depending on the implementation may override the system as described in the PRL’s system table. There can be up to 20 pairs of CDMA SID/NIDs in this list (depending on implementation and possibly subject to handset requirements).

SID/NID Lockout List – The CDMA SID/NID Lockout List describes a list of systems on which the mobile device is prohibited from providing service. Depending upon the implementation this list may be able to hold up to 10 SID/NID pairs and it is stored in the mobile device’s non-volatile memory. A system listed in the CDMA SID/NID Lockout List may over-ride its description in the PRL and be regarded as a prohibited (negative) system during the system selection process.



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Section 3-6


System Scanning

Most Recently Visited Systems• MS often stores the systems on which it most

recently obtained service, and can try them again.

Phone settings may influence system selection and how the PRL is processed.For example, settings may control whether:

• A PRL is enabled at all• A Preferred Mode is to be used• A System Preference exists• Some systems are “black-listed”• Some systems are considered as “Home

Systems”

Geographic Areas and Preferred Systems• Preferences apply only within the scope of the

geographic area• Less preferred systems mean

– Reselection will be attempted– Less battery life– Possibly missing pages during reselection

System Scanning

The mobile device and the network have a symbiotic and yet fickle relationship. A mobile device is always in search of a network to which it can attach. All the CDMA and analog networks can potentially provide that attachment. One of the device’s primary functions is not just to find an attachment, but to find the attachment that suits it best at that moment.

Of course the network can also be a picky partner and reject the attachment advances of the mobile device. The PRL is the mobile device’s little black book of networks it can call upon for attachment and, furthermore, which attachments are considered ‘best’ and better than others. Each network is on a particular channel within a particular band (Band Class and channel) and each server has a particular identity (SID/NID).

In the world of commercial mobile networks there are many systems available to choose from operating on different frequencies and channels. A commercial mobile device, by design, is capable of operating on potentially many different channels and frequencies; it must, therefore, search some or all of the channels that may be able to provide service.

Candidate channels that may provide service are indicated to the mobile, primarily through the descriptions contained in the Acquisition Table of the PRL. The mobile device has to translate this table into a at a list of channels to search—known as a scan list.

System Determination has the responsibility to build the channels to scan and then search those channels for service.



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Section 3-7


Acquisition Table Expansions

Band-class (Band) Mnemonic Expansion Number of

Channels Primary 283 1

Secondary 691 1 A

Both 283, 691 2

Primary 384 1

Secondary 777 1 B

Both 384, 777 2

Primary 283, 384 2

Secondary 691, 777 2

0 (Cellular/800)

Both

Both 283, 691, 384, 777 4

A 25,50,75,100,125,150,175,200,225,250,275 11

B 425,450,475,500,525,550,575,600,625.650,675 11

C 925,950,975,1000,1025,1050,1075,1100,1125,1150,1175 11

D 325,350,375 3

E 725,750,775 3

F 825,850,875 3

1 (PCS/1900)

ANY

25,50,75,100,125,150,175,200,225,250,275,325,350,375,425,450,475,500,525,550,575,600,625.650,675,725,750, 775,

825,850,875,925,950,975,1000,1025,1050,1075, 1100,1125,1150,1175,

42

Use of the Acquisition Table

The acquisition table is generally understood to be a priority ordered list of frequencies to search. As earlier discussions showed, the acquisition table can contain descriptions that encompass a number of channels. To this end the acquisition table is used as an important source to construct a complete list of frequencies and channels to search. These lists are commonly referred to as scan lists and are described further below.

Channel Expansion from Mnemonics in Acquisition Records

Where an acquisition table entry implies multiple frequencies by use of mnemonic, these mnemonics are expanded into the discrete channels and those discrete channels form part of the scan lists. By way of illustration, a couple of examples of this are listed below:

A Cellular CDMA Standard Channels acquisition record to search on both the primary and secondary channels of both the A and B band would be expanded for each of the primary and secondary channels in each cellular band and would yield 4 scan candidates (It is important to understand the meaning of standard channels for Band Class 0 as explained earlier). A PCS Using Blocks acquisition record to search all blocks would expand to use the preferred channels in each of the PCS blocks and would yield 42 scan candidates.

The table shows the channel expansions for the Band Class 0 (US) and Band Class 1.

These are the channels that are scanned to look for a CDMA Pilot, but, this does not mean that they are the only channels on which the device will receive service. Remember that a CDMA system can advertise (and redirect to) other channels that are in use. Additional channels can be communicated in overhead messages, and, the mobile device hashes, using a standardized hashing function, to one of the CDMA channels.



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Section 3-8


About Guard Band Channels

Guard Band Potentially Invalid Channels

Band-class Sub-Band From To

A 312 355

B 334 355

B 645 666

A' 667 688

A' 695 716

B' 717 738

B' 778 799

0

A'' 991 1012

Invalid Channels

While this may not be a rule, a cautionary note here is that for Band Class 0 (800 MHz), scanning some implementations of system determination may enforce the U.S. guard-bands as being invalid CDMA channels. (See Table 15-1 for a description of channels and valid CDMA bands within Band Classes 0 and 1.) This can be significant in building PRLs to roam in CDMA regions where channels usage may not necessarily conform to the North American standard primary and secondary definitions (e.g., Korea and India). The guard band channels for Band Class 0 are shown.

In many implementations this may not be a factor. Which channels, if any, are considered invalid should be checked with the device manufacturer.



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Section 3-9


Most Recently Used Table

MRU Table

• A device stores the list of (typically) 12 systems on which it has most recently operated.

• A system is added to the MRU table upon being successfully selected.

• An MRU table entry contains the following: – A mode

– Band class

– CDMA channel/cellular system

Recent Channel or Most Recently Used List

Mobile devices implementing system determination using the Preferred Roaming List (PRL) typically maintain a Most Recently Used (MRU) table (sometimes known as the Recent Channel List or RCL), which keeps the most recent channels (frequencies) on which service was provided. The number of entries in an MRU is implementation dependent but a typical number may be 12.



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Section 3-10


Scan Lists

Scan Lists

• The list of CDMA channels the device searches for service.

• Scan lists are built dynamically.

• There are three types of Scan Lists:– Normal Scan List

– Better Service Scan List

– System Lost Scan List

Types of Scan Lists

A CDMA mobile device builds a scan list dynamically. Building scan lists, their names and uses, is not standardized and is left to the implementation. Therefore, how the scan list is constructed is a function of the particular vendor’s implementation of system determination but in general is formed from:

channels from the most recently used channelschannels from the acquisition table in the PR

There are different types of scan lists that the mobile device can build that are used by different scans.



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Section 3-11


Normal and Better Service Scan Lists

Normal Scan List• MRU Table

• PRL Acquisition Table

• Duplicate entries deleted

• System preference can cause deletions

Better Service Scan List• Channels in the same GEO

• More preferred than the currently selected channel

• System preference can cause deletions

• Negative systems deleted

Normal Scan ListThe mobile device builds a normal scan list using two sources; the acquisition table and the most recently used set of channels (MRU). The exact way the normal scan list is constructed is implementation dependent.

The acquisition table is generally used as a priority ordered list of frequencies to search, with the first acquisition table entry forming the first entries in the normal scan list.

Where multiple discrete channels are listed, they are normally inserted into the scan list in the order that they appear in the acquisition record; from channel 1 to channel n.

The way in which the MRU channel list is used in the formation of the normal scan list is implementation dependent. The MRU list in some implementations may be placed at the head of the scan list while in others it may be placed at periodic slots in the list, for example, every fifth entry.

Once the two sources are combined, again depending on the particular implementation, there may be some further optimizations that can include actions such as the deletion of:

duplicate entrieschannels caused by suitable identification in the preferenceschannels that can be specifically identified as negative systems

Better System Reselection or Alternate Scan List

This is a list of channels on which more preferred systems than the current serving system, within the current GEO, may be found. It is formed from channels in the same GEO and, as before, system preferences can cause deletions. As always, negative systems are deleted.

The scan containing channels of more systems in the same GEO is referred to as the alternate scan list or the better system reselection scan list.



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Section 3-12


System Lost Scan List

System Lost Scan List• Ordered List of Channels from:

– Last acquired system– Same GEO as the last system– MRU Table– Acquisition Table

• The scan is built with a reacquisition schedule. – Example: Reacq Schedule: REACQ_0_1_2_3_4s

4321 4321

System Lost

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Time

Attempt to acquire other systemsAttempt to acquire lost system

System Lost Scan List

The system lost scan list is an ordered list of channels formed from the last acquired system (that has just been lost), channels in the same GEO as the last system, the recent channel list (MRU), and the acquisition table.

The exact placement of Lost System in this scan list is a direct function of the system lost policies (sometimes called the system loss reacquisition schedule) that are built into system determination. These policies are often specified by a network operator as part of their handset requirements and therefore may vary for devices from different operators.

One such policy is called the REACQ_0_1_2_3_4s schedule, which places the lost system at the head of the scan list then after every other 1, 2, 3, and 4 entries in the scan list. An example of this schedule is shown.

Other puncturing mechanisms are:PING_5 schedule, in which case the lost system is placed at the head of the list and every 5th entry thereafter. 2_7 schedule, in which case the lost channel is probed twice and then again after five other channels have been tried.

If the preference mode is set to other than “automatic,” for example, “digital only,” the scan list is built in the same order as before except that only channels that access “digital systems” added (from the recent channel list and the acquisition table). Similarly, with a preference is set to “home only,” service would not be provided on roam systems.



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Section 3-13


How Long is a Scan?

Difficult to quantify because it depends on: • The speed of the searcher in the device • The type of scan being performed • The number of channels scanned

There are three types of scan:• Full Scan

– The performance of a full scan can acquire a CDMA signal as low as -15 dB Ec/Io.

• Mini Scan– The mini scan is a less rigorous search than a full scan, which is able

to acquire a CDMA signal as low as -13 dB Ec/Io. • Micro Scan

– This type of scan is one that looks for any energy on the CDMA channel.

How Long Does It Take to Scan?

The question often asked in any discussion on system selection is of “how long does it take the phone to scan?” This is often difficult to quantify because it depends on many things that system selection is not responsible for, not the least of which are the speed of the searcher in the device itself and the type of scan being performed. In general, there are three types of scan; a full scan, a mini scan, and a micro scan. The number of channels that can be searched in time interval depends on searcher capabilities of the device.

Full Scan

The performance of a full scan can acquire a CDMA signal as low as -15 dB Ec/Io. Depending on the device (implementation, processor speeds, etc.) a full scan can takes as long as 1.2 seconds all the way down to as short as between 200–300 ms.

Mini Scan

The mini scan is a less rigorous search, than a full scan, which is able to acquire a CDMA signal as low as -13 dB Ec/Io. Again, the speed of a mini scan is device and implementation dependent and can anything between 100 and 600 milliseconds (approx).

Micro Scan

This type of scan is one that looks for any energy on the CDMA channel. If energy is detected, then a mini scan may be performed. The time for such a scan is device and implementation dependent and may take as long as 100 milliseconds.



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Section 3-14


System Selection

Most Recently Visited Systems• MS often stores the systems on which it

most recently obtained service, and can try them again.

Phone settings may influence system selection and how the PRL is processed, e.g., settings may control whether:

• A PRL is enabled at all.• A Preferred Mode is to be used.• A System Preference exists.• Some systems are “black-listed.”• Some systems are considered as “Home

Systems.”

Geographic Areas and Preferred Systems

• Preferences only apply within the scope of the GEO.

• Less preferred systems mean:– Reselection will be attempted– Less battery life– Possibly missing pages during

reselection

System Selection

Once a system is detected by the scanning process, the only thing that has been determined is that a CDMA or analog system has been found. As yet, no selection criteria have been applied to fulfill the goal of system determination, i.e., find the best system to provide service.

This second stage of is often referred to as the system selection process. It is during this stage that priorities and preferences are applied. Remember that exactly when system determination is invoked, even how it is performed, is not standardized. Nonetheless, the general behavior is well understood and it is still possible to describe the typical events that may cause system determination to happen. Some of these are caused by the mobile and some of these are caused by the network.

In earlier discussions the selection process was left as a generic statement of apply selection criteria. In this section the aspects of system selection process are considered. Shown is a generic example of the elements that all CDMA system selection processes must exhibit.

The diagram also shows the typical stages at which the PRL and device settings are used in the system determination process.



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Section 3-15


System Types

A system defined in the PRL for which the Neg/Pref field is set to “Negative.”Negative

An acquired system not listed in the PRL. If the PRL has PREF_ONLY=FALSE, service may be provided on an available system.

Available

Preferred but not the most preferred system or negatively preferred system in that GEO.Less Preferred

The most preferred system its GEO.Most Preferred

Defined by the PRL as “Preferred.”Preferred

Notes



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Section 3-16


When System Selection Occurs

System selection occurs:

• MS power-up

• Service on less preferred system

• After a call

• System lost

When System Selection Occurs

There are various conditions that can cause system selection to occur. Some of the more common ones are:

MS Power-up. When the device is switched on and looks for service. This is sometimes referred to as initial acquisition.

Less Preferred Service. Service from any system that is not the “Most Preferred” generally causes the device to attempt to obtain service on the system that the PRL has declared as the Most Preferred. This is often referred to as [Better Service] System Reselection.

Call Termination Reacquisition. After a call, upon release of the traffic channel, the mobile will begin to look for the system again.

System Lost. When the mobile detects that it has lost the signal of its serving system, it generally begins to search for service again.



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Section 3-17


Types of System Selection

• Device detects loss of signal of its serving system• Begins to look for service again• Referred to as a System Lost Scan

System Lost

• Device releases the traffic channel • Looks for the system again• Referred to as Call Termination Reacquisition

After a call

• Service is not on the Most Preferred• Generally wait some time and try again to get to Most Preferred• Referred to as System Reselection • Wait period is the system reselection timer (around 3 minutes)

Service on Less Preferred System

• Device is switched on and looks for service • This is sometimes referred to as Initial Acquisition

MS Power-up

Initial AcquisitionWhen the mobile is powered on, it performs initial acquisition and attempts to acquire a system on the channels of the normal scan list, starting from the top. If a system is acquired that is not listed in the PRL, then that system is recorded as an available system (on an available systems list) and scanning progresses to the next entry in the scan list . If a system is acquired that is listed in the PRL’s system table and is the most desirable system in that specific GEO, then service is provided on that system and all scanning stops until the system is lost. An acquired system that is listed in the PRL (system table) that it is not the most desirable system in the GEO will cause the device to search using the better service scan list. Better Service ReselectionWhen the mobile device ends up providing service on a “less-preferred” system[1] (which is any system that is not the most preferred), “Better Service Reselection” occurs (often simply referred to as reselection). This is the implementation of a policy something like “OK, stay here for now but keep trying to get to a more preferred system until operating on the most preferred system.” This continues until the most desirable system in the GEO is acquired or the system is lost. The device implements this policy by use of a reselection timer, reselection period, better system scan list, and better service scan.Call Termination ReacquisitionUpon entering idle state, following a call release, a CDMA device normally performs a reselection, often referred to as call termination reacquisition. This reselection is performed a fixed amount of time (typically 4 seconds) after the end of a call when the mobile is not on the most preferred system. System LostWhen a mobile device declares it has lost a system, it invokes its system lost reselection policy. The device implements this policy by use of a system loss reacquisition schedule, system loss scan list, and system loss service scan. The system loss reselection is similar to the better service reselection except for the earlier noted changes in how the scan list is constructed. The “schedule” of attempts to reselect the system that has just been lost is set and driven by the construction of the system lost scan list. As in better service reselection, if a system is acquired and it is less-preferred, then better service reselection will be performed. Often the system determination will search through the GEO first. The signal level that a mobile device declares it loses a system is implementation dependent. A CDMA system is normally unusable an at Ec/Io of -16 dB or lower.



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Section 3-18


Identifying an Acquired System in the System Table

• Exactly how an acquired system is matched against the system table is determined by the matching policies, which vary across implementations.

• Typical general behavior in terms of:– Index keys into the system table– Wildcards in systems description– Band Class and channel matching

• Index key into the System Table– SID– NID – Band Class (channel in some implementations)

• Wildcards– In most implementations, the finest granularity of match is the one used (i.e., most

unambiguous). – When wildcards are used, the general order of resolution tends to be SID resolution

followed by NID resolution.• Band Class and Channel Matching

– Most implementations the level of granularity would be limited to the Band Class. – Some implementations may perform channel matching.

Matching System Table Described Systems

Once a system is acquired, it must be identified in the system table so as to locate the GEO within which the device is currently operating. Once located, the system’s criteria must be applied. Identifying a system record in the system table is often referred to as matching. Exactly how an acquired system is matched, against the system table, is determined by the matching policies, which can vary widely across implementations. Nonetheless, all will exhibit general behavior in terms of:

Index keys into the system tableWildcards in systems descriptionBand Class and channel matching

Index Key into the System Table

A system is matched in the system table by a composite index of the system’s broadcast identity together with the description of the frequency on which the system is located. The component key fields of the composite index are SID, NID, and Band Class (channel in some implementations). This composite index is further complicated by the fact that these component elements can have non-unique values. A PRL wild card value for SID will match any broadcast SID and, similarly, a wild card NID value will match any broadcast NID. Previous discussion showed how acquisition records can contain mnemonics, which expand to multiple channel values. The presence of these non-unique values means that matching criteria are required in order to match an acquired system to a particular system entry in the PRL’s system table.

In most implementations, the finest granularity of match is the one used (i.e., most unambiguous). When wildcards are used, the general order of resolution tends to be SID resolution followed by NID resolution.

Band Class and Channel Matching

If the part of the index key that was ambiguous was the Band Class and band/channel then discrimination is less clear. In most implementations the level of granularity would be limited to the Band Class; however, there are some implementations that perform channel matching. Any use of differences within the Band Class to differentiate systems should be verified with the mobile device vendor to ensure the desired behavior will result. Any attempt to block service from one provider on a particular channel but allow it on other channels in the same Band Class would require system determination implementation support and perform matching down to the channel level.



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Section 3-19


Applying Priorities in Selecting a System

• System selection process must decide whether to: – Stay on the acquired system– Continue to look for one that is more preferred

• The criteria and how they are applied vary across implementations.

• All will exhibit general behavior in terms of:– Roaming preference and Home SID/NID/List– SID/NID Lockout List– Priority– Equal Priority Selection Criteria

Applying Priorities in Selecting a System

Having located a system within its GEO, the system selection process must decide whether to stay on the acquired system or continue to look for one that is more preferred. For the first acquired system, this is a decision of “Do I stay or keep looking?” and then, for situations of reselection, the question becomes a comparison—“Is the newly acquired system better than the one I am on?” Exactly what these criteria are and how they are applied can vary widely across implementations. However, all will exhibit general behavior in terms of:

Roaming preference and Home SID/NID/List.SID/NID Lockout List.Priority.Equal Priority Selection Criteria.

The first two can be considered filters that are applied to the system table to modify the set from which a selection can be made. The latter two can be considered as choice criteria from the resultant set of selectable systems.



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Roaming Preferences

Earlier in this section we noted that the roaming preference can affect system selection. The roaming preference setting can be a system table filter that reduces the systems available for selection. If the roaming preference has a setting of “Home Only” then any system in the system table with a roaming indicator other than “Roaming Indicator Off” becomes an unavailable for selection. If the device has a populated “Home SID/NID list,” then, any systems listed become identified as selectable non-roaming systems. Use of this list with a PRL has the following side effects:

Systems in the list that are not in the PRL enter the selectable set regardless of the PREF_ONLY setting in the PRL properties. Systems in the list that are listed in the PRL as roaming systems become selectable as non-roaming systems. Systems in the list that are listed in the PRL as negative systems shed their barred status and become selectable.

The “Home SID/NID list” is a legacy from the days prior to PRLs and is typically not used in conjunction with a PRL.

SID/NID Lockout List

This list is effectively a system table filter. Any system listed becomes unavailable for selection. Use of this list with a PRL has the following side effects:

Systems that are listed in the PRL are barred from selection regardless of their description in the PRL. Systems that are not in the PRL are barred from selection as an available system regardless of the PREF_ONLY setting in the PRL properties.

The “SID/NID Lockout list” is a legacy from prior to PRLs and is typically not used in conjunction with a PRL.



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Section 3-21


Applying Priority

Priority• Priority is the factor for system selection within a GEO.• It is the indicator of whether a system is most preferred or not. • Scope of priority is limited to within the GEO. • The prime objective of system selection is to get to the most preferred

system. • The same priority can be applied to multiple systems. • When systems have the same priority they are all equally selectable as

the others.• Priority alone may not be enough, such as:

– Two systems have the same preference and different roaming indications.– Selection would require selection between two GEOs.

PriorityPriority is normally the primary distinguishing factor for system selection within a GEO and is the major indicator of whether a system is most preferred or not. Remember that the scope of priority is limited to within the GEO. The prime objective of system selection is to get to the most preferred system. Each system record does not require a unique priority; the same priority can be applied to multiple systems. When systems have the same priority they are all share level in the pecking order of systems. This means that situations arise where priority does not distinguish between systems. In most cases this is perfectly fine and means that any one is as equally selectable as the other. However, there are situations where priority alone may not be enough, such as:

Two systems have the same preference and different roaming indications.Selection would require selection between two GEOs.

Equal Priority, Different Roaming IndicatorWhere two systems in the same GEO are compared and the only discernable difference is the roaming indicator, then, in general, a system will be more preferred if it is not roaming.Geo Changes and System SelectionIn the situation where the acquired system and the current serving system are listed in different GEOs, there are normally some rules to follow to ensure that the “best system” is used. Some typical rules are:

In the case where only one of the systems is listed in the PRL, then the PRL system would normally be preferred.Where both systems are listed in different GEOs and the roaming indicators are different, then typically “roaming indicator off” would be preferred over “roaming indicator on” or “roaming indicator flashing;” and “roaming indicator on” would be preferred over “roaming indicator flashing.”When one of the systems is of a higher preference order in its GEO, then it would probably be preferred over the other. All other things being equal, the system operating on the channel that appears first in the acquisition table may be preferred.If one system is CDMA and the other is AMPS, typically the CDMA system would be preferred over AMPS.



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Section 3-22


Multi-GEO SIDs

• A SID in more than one GEO is called a multi-GEO SID.

• When a multi-GEO SID is acquired, a composite GEO is created.

• The composite GEO is used to build the more preferred list (for better service reselection) out of all such GEOs.

Acquiring a System That Appears in Multiple GEOs

A SID that is repeated in more than one GEO is called multi-GEO SID. When a multi-GEO SID is acquired, a composite GEO is created that is a combination of all the GEOs within which the multi-GEO SID is found. The first GEO in which both systems appear typically becomes the pivot point and is used to determine the relative priority of the systems in the other. The composite GEO is used to build the more preferred list (for better service reselection) out of all such GEOs.

The figure shows the combination of two GEOs into a composite GEO when a Multi-GEO SID is encountered. In the example the composite GEO pivots on the position of the SID 4 in the first GEO encountered.



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Section 3-23


Available System and “Open” PRLs

• An acquired system not described by the PRL is called an available system.

• Remembered on an available systems list.

• One of the properties of a PRL is the “Preferred Only” property which takes a TRUE or FALSE value: – A TRUE value indicates a “Closed PRL.”

Only systems explicitly listed in the PRL.

– A FALSE value (0) indicates an “open PRL.”If no PRL system can be found use an available system.

May not prioritize CDMA systems over analog systems.

Available System and “Open” PRLs

At any time, during any type of system selection or reselection, when a system is acquired that is not described by the PRL, then that system is recorded as an available system (on an available systems list).

One of those properties of a PRL is “Preferred Only” property.

This property takes a TRUE or FALSE value.

A TRUE (1) value indicates a “Closed PRL,” which means that service may not be provided on any system that is not explicitly listed in the PRL.A FALSE value (0) indicates an “Open PRL,” which means that service can be provided on a system from the available systems lists if no preferred system can be found. Where more than one system is on the available systems list system selection may prioritize CDMA systems over analog systems.



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Section 3-24


Understanding Reselection

• Reselection timer and reselection period. • Side effects of reselection:

– Scanning consumes more power than simply being idle on a channel.

– Reselection affects battery life. – When a mobile device is searching for service:

It is not monitoring overhead channels (can miss mobile terminated calls or SMS messages). It is using more power than idle.

– Poorly designed GEOs:Place two disparate regions (or countries) in the same GEO and then make one region the most preferred.Place one system in a GEO that is only available at the border of that region and make it the most preferred.

– Better Service Reselection while on an AMPS system.

Better Service Reselection

When the mobile device ends up providing service on a “less-preferred” system[1] (which is any system that is not the most preferred), “Better Service Reselection” occurs (often simply referred to as reselection). This is the implementation of a policy something like “OK, stay here for now but keep trying to get to a more preferred system until operating on the most preferred system.”This continues until the most desirable system in the GEO is acquired or the system is lost. The device implements this policy by use of a reselection timer, reselection period, better system scan list, and better service scan.

Reselection Timer and Reselection Period

The mobile device has a timer that is set running when service is offered on any less preferred system. The timer runs for a period of time, known as the reselection period, after which the mobile device again attempts to acquire the most preferred system in the geographic region. The reselection period is typically three minutes.

Better Service Scan

Expiration of the reselection timer causes the device to search for more preferred systems in the same GEO. If the device is obtaining service from an “available” system, it searches all channels in the acquisition table. If reselection acquires the most preferred system, then service is provided and the reselection timer is not set, i.e., no more reselection will occur. If a more preferred, but not the most preferred, system is acquired then service is provided and the reselection timer is reset. Better service reselection continues once the timer expires.



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Side Effects of Reselection

Reselection means that the device is scanning the RF environment; such scanning consumes more power than simply being idle on a channel. Reselection, therefore, impacts battery life. When a mobile device is searching for service, it is not monitoring overhead channels, such as the quick paging or paging channels. Reselection, therefore, can cause missed pages (missed mobile terminated calls or SMS messages.) Because of this, preferences in a GEO should be designed so as to strike a balance between the number of preferred systems and the user experience (in terms of battery life and missed pages). Where there is little chance of a device obtaining the most preferred system, reselection is not useful. This happens in situations where further geographic separation is applied, e.g.:

Placing two disparate regions (or countries) in the same GEO and then making one region the most preferred.

Placing one system in a GEO that is only available at the border of that region and making it the most preferred.

Each of these circumstances can cause reselection to occur frequently when served by a less preferred system, even though there is little or no chance of obtaining better service.

Better Service Reselection While on an AMPS System

In some implementations, AMPS is considered to be a generally less desirable system and the reselection period while being served on an AMPS system is often lower. This can be two minutes or as low as one minute, depending on factors such as device type (tri-band or dual band) and the implementation.



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Section 3-26


SID, NID, or Band Class Change

• Changes in SID, NID, or Band Class causes System Selection to be revisited.

• SID, NID, or Band Class change can happen through:– Channel List Message

– Idle Handoff

– Hand Off Direction

– Extended Channel Assignment Message

– Redirection

Changes in SID, NID, or Band Class

The management of the recent channel list is implementation dependent, but typically the band and channel from which the device acquired the CDMA Sync channel is placed in the recent channel list. During idle operation, if the channel changes, the new channel is placed in the recent channel list, provided that the band and channel is in the acquisition table and the device is not operating on an available system.

Questions often arise on behavior when any changes that occur in the SID, NID, or the Band Class change while in idle mode. There are two aspects to consider here:

What gets recorded in the Recent Channel List or MRU?How is the PRL involved?

In some implementations a change alone in the Band Class may cause no update to the recent channel list, while in others the new Band Class and channel is placed in MRU, regardless of PRL matching. Typically, any change in any one of the SID, NID, or the Band Class would re-invoke system selection using the PRL. If the newly encountered system is not the most preferred, better service reselection would be performed. There are various network conditions or messages where a SID, NID, or Band Class may occur which are discussed below. However, it should be noted that these messages more often occur without any change in any of these three items. Some of the situations where a SID, NID, or Band Class change can be detected by the mobile are:

Channel List Message Idle Handoff

Hand Off Direction Extended Channel Assignment MessageRedirection



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CDMA Channel List Message

A market may be served by multiple frequencies; when a CDMA Base Station operates on more than one channel it indicates the channels in use to the mobile device in a CDMA Channel List Message (CCLM). Upon receipt of this message, using a predefined hashing algorithm, the device calculates on which of the listed channels it should operate. If the device hashes to a channel in a different Band Class, or if a change in the SID or NID is detected on the new channel, the device will reenter system selection.

Idle Hand-off

A mobile always looks for the strongest pilot. Moving to a new Base Station that has different Band Class, SID, or NID causes system selection to be performed to acquire the most preferred system in the same GEO. If it cannot acquire the most preferred system, it re-tries when the reselection timer expires.

Hand-off Direction

The CDMA General Handoff Direction Message (GHDM) may contains Band Class and CDMA Channel information for the mobile device to use. A Band Class change causes system determination to be consulted. If there was no Band Class change but the new system has a different SID or NID, then system selection is performed.

Redirection

A system may issue a Global System Redirection Message (GSRM) to direct devices to a different frequency. The GSRM can contain Band Class and CDMA Channel information for the mobile station to use for reacquisition. A Band Class change causes system determination to be consulted. If there was no Band Class change but the new system has a different SID or NID, then system selection is performed.

Extended Channel Assignment

In idle mode, the network can use the Extended Channel Assignment Message (ECAM) to redirect the mobile to a paging channel. This ECAM may optionally include a new Band Class and CDMA Channel. A Band Class change causes system selection to be performed. If there was no Band Class change but the new system has a different SID or NID, then system selection is performed.



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Section 3-28


Avoidance of Unusable Systems

• Any of the following would generally render a system unusable:

– P_REV mismatch– System’s SID/NID is rejected by PRL– Sync channel is acquired but not the paging channel– Bad OHM– Registration is rejected– Max access probes

• Unusable systems would normally be avoided.– Avoidance period would be dependent on implementation

Avoidance of Unusable Systems

A mobile device may encounter a system upon which it cannot provide service. A mobile device can declare a system to be unusable for a number of reasons, some of which are:

P_REV mismatch

System’s SID/NID is rejected by PRL

Sync channel is acquired but not the paging channel

Bad overhead messages

Registration is rejected

Max access probes

Most system selection implementations will avoid systems considered to be unusable; although for exactly how long, is implementation dependent. A typical time to avoid an unusable system would be 30 to 60 seconds—normally referred to as the avoidance timer. Avoiding a system does not imply that system is reacquired after avoidance timer expires it just means that it is eligible to be scanned again. During the avoidance time the channel is omitted from the normal scanning process. When the avoidance timer expires, the channel reenters the next scanning schedule.

Max-Access Probe Exit Scan

When an access attempt fails with maximum number of permitted access probes[1], the mobile device would normally use a maximum access probe exit scan list for reacquisition. This list is similar to a power up scan but lacks the channel on which the access attempt failed.

[1] Access probe is a term used to collectively mean a system access message, sent on the access channel, and the specific power level with which it is sent. If the mobile device does not get a response, it sends subsequent access probes (same message at increased power levels). Often described as raising its voice until it is heard. There is a predefined maximum number of probes a device can send and a maximum power it can use.



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Section 3-29


No Selectable System

No Selectable System and scan list is exhausted and service cannot be provided.

• Behavior is implementation-dependent.• System determination typically resets the scan list and starts

scanning again. • If no service is found, the device enters power-save mode. • A mobile device periodically exits power-save mode.

No Selectable System

If the scan list is exhausted and service cannot be provided, system selection behavior is implementation dependent (and may be specified by the operator in their handset requirements). Typically, system determination will reset the scan list and start scanning again. If no service is found after scanning for a period of time (10-15 minutes), the device enters power save mode. A mobile device will exit power save mode periodically to search for service again.

The figure shows a simplified timeline of the selection behavior, when no service is found. Some points to bear in mind:

The length of time of the initial search period is implementation dependent.The length of time the mobile sleeps between searches may lengthen by some expansion factor as subsequent searches do not find service. Any increasing sleep window behavior and the expansion factor is implementation dependent.The length of time the mobile searches during wake up times may decrease by some compression factor as subsequent searches fail to find service. Any decreasing search window behavior and the compression factor is implementation dependent.Often any user intervention, such as a key press, can reset the power save cycle and recommence with the search window reset to the initial search time.

Some or all of these behaviors may in fact be included in an operators’ handsets specification.



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Section 3-30


How the Preferred Roaming List is Used –Section Review

1. What is system determination?

2. What are three preference settings that can affect system determination?

3. What are two ways to prevent a user from acquiring a particular system? Which one is preferable and why?

4. What are two ways to identify a particular system as a home system? Which one is preferable and why?

5. What are the implications of selecting a less preferred system?

Review

1. System determination is the process of attempting to, as quickly as possible, identify and acquire the best system upon which to operate.

2. Three preference settings that can affect system determination are:

Mode Preference (e.g., CDMA only)

Band Preference (e.g., Band class 1 only)

Roaming Preference (e.g., home only)

3. A device can prevent a system from being acquired by:

Including it in the SID/NID Lockout List

Identifying it as negative (i.e., not preferred) in the PRL system table

Identifying systems as negative in the PRL is preferable because it allows control over system selection to remain within the PRL. Using a SID/NID Lockout List essentially complicates system selection by introducing a separate mechanism outside of the PRL to do what the PRL is capable of doing natively.

4. Home systems can be identified by:

Including them in the Home SID/NID List

Identifying them as non- roaming systems (e.g., Roam_Ind = OFF) in the PRL system table

Using the roaming indicator in the PRL is preferable because, as with the previous question, it allows control over system selection to remain within the PRL.

5. When less preferred systems are acquired, devices periodically perform reselection in an attempt to find a more preferred system. This results in less battery life and potential missed pages during reselection attempts.



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Section 3-31


How the Preferred Roaming List is Used –Section Review (continued)

6. What are scan lists and how do they relate to the PRL?

7. What are the three types of scan lists?

8. What is a composite GEO?

9. Scenario: GEO 1: SID 10, priority 1SID 99, priority 2

GEO 2: SID 70, priority 1SID 80, priority 2SID 99, priority 3

Handset is receiving service from SID 33.

What SIDs and priorities are used during reselection?

10. What is the difference between “preferred” and “available” systems?

6. A scan list is a list of candidate channels used by the device to search for service. Scan lists are dynamically built using PRL information, the Most Recently Used (MRU) table, and system preferences.

7. The three types of scan lists are:Normal Scan List – used for initial acquisition (i.e., during power up)Better Service Reselection (a.k.a. Alternate) Scan List – used to look for a more preferred systemSystem Lost Scan List – used when an acquired system is lost

8. A composite GEO is a combination of multiple GEOs. When a SID appears in more than one GEO (i.e., a multi-GEO SID), a composite GEO is created that combines of all GEOs containing that SID. This composite GEO is used to build the more preferred list for Better Service Reselection.

9. Because SID 99 is a multi-GEO SID that exists in both GEOs 1 and 2, a composite GEO comprising SIDs in both GEOs is formed with priorities that pivot around SID 99 as shown below:

SID 70, priority 1SID 10, priority 2SID 80, priority 2SID 99, priority 3

Once selected, the priorities relative to the selected SID would be used to determine whether to reselect again. For example, if SID 10 is selected, no further reselection would be performed because it is most preferred in GEO 1. However, if SID 80 were selected, the handset would continue to look for a more preferred system, because it is not most preferred in GEO 2.

10. Preferred systems are defined in the PRL. Available system are not. Available systems only occur with open PRLs (i.e., Preferred_Only = False). If the PRL is open and no preferred systems can be located, other systems identified during scanning are considered available.



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Comments/Notes


PRL Technical WorkshopSection 4: PRL Process

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Section 4-1


Section 4: PRL Process

4SECTION

PRL Process

Notes



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Section 4-2



Describe the process for developing and managing PRLs.Explain source data management.Define change analysis.Explain what is involved in PRL production.Explain what is involved in PRL testing.List the products of a new PRL release.Explain the PRL distribution process.List the parts of a PRL process timeline.

Notes



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Section 4-3


Why is a PRL Process Necessary?

CDMA system selection function is a search engine.

• It looks for a CDMA network. • PRL is considered to be the search data.• System selection search engine is only as good

as the PRL database it searches against.

A good PRL is the output of a solid process.

• A PRL is as only as good as the source data used to build it.

• Careful management and currency of input data is essential.

• Achieving a good and manageable PRL requires management of the following:

– The input data from various sources– In-service PRLs– Dependency information between the two

Weakness in the PRL process can lead to a perception by:

• The operator – that the roaming process is overly arduous.

• The end user – that the service is either unavailable or unreliable.

Distribution

Release

Testing

Production

Source Data Control

Source Data

Change Analysis

New Release Data

Pre-Release Data

CurrentRelease

Data

Why is a PRL Process Necessary?

The PRL is a database that the system selection process uses to determine where to search for systems and which systems are the best ones for service.

Any search result is directly related to the sources that are searched. Since the PRL is the searchable data for the system selection search engine, the system selection quality depends on the quality of the search data that the PRL database provides.

One of the most important aspects of a PRL is that it is the output of a process. The contents of the PRL can only ever be as good as the source data that is used to build it and, consequently, the system selection capability of the handset can only be as good the data in the PRL provided to it. The source data used to build a PRL can come from many disparate sources. The key here is that the careful management and currency of input data is essential to producing a reliable, maintainable and traceable PRL design.

Achieving a good and manageable PRL requires a solid process that carefully manages the input data all the way to the deposit of the PRL into the mobile device. Any weakness in this process can ultimately lead to the perception by the operator that the roaming process is overly arduous.

Perhaps more harmful, once unleashed into the customer domain, there is the risk that a poor PRL can lead to a perception, by the end user, that the network and service have poor coverage, cannot or do not allow roaming, or are unavailable or just unreliable.



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Section 4-4


PRL Data Source Management

Internal network data • SID and NID information from network

planning and works

Internal commercial data• Commercial data ensures that the appropriate

preferences are applied

External roaming partner data

Derived sources

Data collection from sources• Internal data sources• External Data Sources• Derived Sources

Configuration management• Cataloging• Storage• Version Control

Home Operator

Roaming Partner

Network Data Admin TDSPRL Data

Admin Tariffs & Commercial

Network Data Admin

Roaming Partner

Network Data Admin TDS

1

23

Source Data ControlSource Data

Source Data Management

The source data to build a PRL can come from a number of sources, both internal and external:

Internal – from the Network Data department. SIDs and NIDs are a key part of the network configuration data that must be provided to various other interested departments, including the department responsible for PRLs. SID and NID information result from any number of other processes within the operator organization, which can include initial network planning, ongoing network build-out, network modernization and upgrade or ongoing network optimization and rationalization. Any of these processes can result SIDs and NIDs being assigned, reassigned, or consolidated.

Internal – from the department responsible for negotiated wholesale roaming tariffs. In the case where more than one roaming partner is used in particular roaming markets, these tariffs generally provide the basis for preferring one network over another. Over time, tariffs may be renegotiated and preferences may change; at that point, it becomes commercially important to ensure that the current preference is applied to the appropriate roaming partner’s network for system selection.

External – from roaming partners. Data is exchanged between operators in a format commonly referred to as the Technical Data Sheet[1] (TDS). The TDS contains sections describing the Broadcast SID/NID information and the associated BIDs of the commercial markets in the roaming partner’s network.

Source data must be managed, or building and tracking PRLs can become an arduous task. Management can be achieved with something as simple as manual logs or in some electronic form such as a database, spreadsheet, or even a commercially available configuration management system. There is 100% certainty of change; business changes and new roaming partners cause changes to the network information. A version control process ensures that future change (in either the production PRLs or personnel that produce them) is, at least, manageable.

[1] CDG Document #81 provides the general format for the Technical Data Sheet that is used between carriers. In many cases carriers’ particular formats may vary but the general content will be similar.



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Section 4-5


Change Identification Analysis

• Examination of new data

• Identifying affected released data

• Identifying extent of any new PRL production required

Change Analysis

Source Data

TDS Network Commercial PRL-a PRL-zPRL-z

Released Data


Knowing which information is the most current, and where it is located, is a critical first stage. However, when any information source changes, some key questions arise:

Does this change affect any of the currently released or in-development PRLs?If so, which ones?If so, is this a change I need to, or can afford to, absorb at this time?If so, how and when should this change be propagated to the PRL work stream?

These questions, in essence, describe the functions of change analysis for the PRL process. Depending on how automated or linked configuration record keeping is, this work function can be an automated process or manual analysis. Either way, the goal is examining new data to identify any affected released data.

Once the affected PRLs are identified, the analysis should extend to figuring out the scope of the change, and how it should be included. Many factors affect the priority of an identified change, such as the following:

Resources available to make the changeRevenue (or other) impacts of [not making] the changeRelative importance of the affected area to the customer baseAt what point in the PRL process new data arrives; i.e., cut-off or data-freeze dates.

After all of the factors discussed above are considered, the result is described in the change details and/or work orders for PRL production.



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Section 4-6


PRL Production

PRL can be constrained by:• Physical storage space available in device• Regional, national and international categorization• Staff availability to manage multiple options

PRL production should consist of:• Solid design and implementation practices• Configuration management and control

Production

Source Data

Released Data

Change Details

Pre-release Data

PRL Production

Ideally, when beginning production of a PRL, all source data is known and current, and changes that affect a PRL are identified.However, the following constraints can affect how a PRL is designed:

Physical storage space available in a particular device. Storage space available for a PRL can range from 1 KB to more than 6 KB. Common limits are 1K, 3K, 4K, 6K, and 8K.As a result of the size constraint or otherwise, PRLs may be separated by regional, national, and international categorization.Staff availability to manage multiple options. While there may be many novel ways to design PRLs, in the real world operators have very real constraints on the resources available to produce and maintain them. Other process element constraints. For example, in the testing phase: resources available to test multiple PRLs. In the distribution phase: the number of PRLs that can be distributed by the OTA systems.

PRL production may face these constraints; however, it should always use solid design and implementation practices, backed up with a reliable record keeping system. These core elements directly relate to how maintainable and traceable PRLs are. For example, they should address how the PRL_ID property is populated, and should provide sufficient information to yield the full configuration trail of the PRL.

When produced without a solid and traceable process, a PRL becomes exponentially more expensive to revise. If the PRL design is not documented, design decisions can be lost and errors (previously designed out) can creep back in, causing extra productioniterations.

The expense of an error in the PRL is directly related to the stage at which the error is detected. If the PRL is already widelydistributed, there is an inherent reluctance to modify it. This reluctance increases as staff turnover occurs, and, in the absence of documented design, some of the learned “black art” is lost and those lessons have to be relearned. This anxiety can only be mollified by the presence (and use) of solid process. At the very least, each PRL release should clearly identify any and all source data, constraints applied, and design decisions made. This process can be as automated or as manual as the operator desires, as long as it captures the aforementioned essential elements.



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Section 4-7


PRL Testing

Internal Testing• Own network test facility• Partner’s network test facility

Field Testing• Home Market Field Testing• Home Country Field Testing• Foreign Country Field Testing

Test Equipment• Ensuring all variants of PRL and system determination are covered

Testing

Production

Pre-Release Data

Testing

Production

Pre-Release Data

PRL Testing

In PRLs, as with most things, the earlier an error is discovered, the easier it is to address. However, because a PRL is describing so many different radio environments and serving systems (both local and remote), the number of test traces tends to be high and the configuration of a test harness is not as straightforward as it might be for some other test scenarios.

Testing rigor generally depends on the time and resources available. Various forms of testing can be applied, both with a PRL in a standalone environment without a handset (off-target testing) and with a PRL loaded into a handset that is then placed in a real RF environment (on-target testing).

On-target testing can take various forms. If an operator has access to a network test facility, radio environments can be simulated and a device loaded with the pre-release PRL. If no such facility exists, in-market testing can be performed. Since this is the most expensive form of testing, fraught with coordination difficulties, it tends to test only a selective subset of the PRL. These in-market tests can include:

Home market field testingHome country field testingForeign country field testing

PRL testing is addressed later in this workshop, including various types of testing and some sample tests that can be performed.



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Section 4-8


Release and Distribution

Release Products• New PRLs

• New TDS

• Release Numbers

ReleasePre-Release Data

New Released Data

Release of New PRL

After a pre-release production PRL is successfully tested, it is generally given the seal of approval and elevated to a status of “released.”

Often the group that builds a PRL to include roaming partners is also responsible for releasing their own network information to roaming partners. The release products of such a group include the following:

New PRLs

New Technical Data Sheets (TDS)

For any release, it is important to include a product identity (i.e., identifying what is being released), such as a date or release numbers:

PRL list ID – allows a label to be placed in the PRL to identify which release product it is.TDS information – often uses a document number or the release date in the title and the TDS itself to identify the release number.

The release of a new TDS can be the result of diverse activities across a network such as core network changes, SID consolidation, network build-out, technology upgrades, etc. All of these can directly affect roaming partners and must be communicated in a timely manner.

Not all TDS changes require partners to change their PRL (i.e., no effect on inbound roaming access) but core network changes such as line ranges, point codes, switch IDs, or Temporary Local Directory Number (TLDN) ranges can have a dramatic effect on outbound roaming and negatively affect the ability of inbound roamers to receive calls.



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Section 4-9


PRL Distribution

Non-Customer Targets• Electronic file transfer to distribution hubs

• Physical file transfer to distribution hubs

In-Service Targets• Notification and user-initiated OTASP

• Network initiated OTAPA

• Notification and service center upgrade

Non-CustomerTargets

In ServiceTargets

Distribution New Released Data

Identifying the Upgrade Targets for a new PRL

The distribution of a new release of a PRL generally involves two phases:

Phase 1 addresses non-customer targets.Phase 2 addresses the in-service targets.



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Section 4-10


PRL Distribution – Non-Customer Targets

Distribution Hubs • Action time, • In-service date

Customer Service Centers• OTASP/OTAPA platforms• Walk-in centers

Roaming Partner Test Groups• (for any previously distributed handsets

and/or R-UIMs)

Current Inventory• Retail outlet inventory• Warehoused inventory

New Inventory• Handset manufacturers

Non-CustomerTargets

In ServiceTargets


Non-Customer Targets

Non-customer targets can be internal distribution hubs. In these cases, the PRL will be released with a specific date and/or action time from which it will be placed in-service. Examples of these distribution hubs include:

OTASP platformsRoaming partner test groups (for any previously distributed handsets and/or R-UIMs).

If inventory must also be updated and the OTASP platforms cannot be used for this purpose, other hubs may require the release, including the following:

Retail outlet inventoryWarehoused inventoryHandset manufacturersCustomer service centers



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Section 4-11


Distribution – In-Service Targets

Changes may not affect all in-service PRLs. Distribution can be prioritized by: • PRL ID • Device Type • Customer Service Area• User (MIN/ESN)

Revenue-sensitive data analysis may be required. • Determine which subscribers have incurred highest revenue in areas affected by changes.

– Requires operational support systems implementation in the operator’s network. – Example: query reports of customers with significant call revenue on a BID that relates to a

changed SID.

Non-CustomerTargets

In ServiceTargets


Identification of In-Service Customer TargetsChanges may not affect all in-service PRLs. Also, it may be desirable to prioritize the update targets using one of various possible criteria:

By PRL ID Every PRL has a field that describes its identity. Any in-service mobile with a PRL version identity that has been updated can be identified as a target for update. To achieve this, run a query report against the operational support system that holds the data relating PRL version ID to MIN and or ESN.

By Device TypeAn operator may have PRL identities further classified and versioned by device type. Here it would be necessary to run a query report on the operational support system that maintains the device type to MIN/ESN relationship information.

By Specific Customer(s)Often the two previous target identification methods may yield a large list of in-service handsets that require an updated PRL. It may be beneficial to prioritize such a list to ensure the most affected network users are updated first. This could be important when upgrading the PRL directly affects roaming revenue. Example: frequent roamers to a foreign market where significant change has occurred, or where a change in an inter-operator, commercial wholesale relationship makes one partner more preferred than previously. Some form of usage data analysis is required to determine which subscribers have roamed onto SIDs that are affected by changes in the new PRL. How this is done depends on the implementation of operational support systems in the operator’s network. Example: query reports of the billing system to determine which customers may have significant call revenue on a BID that relates to the SID of the area that has changed.



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Section 4-12


PRL Process Timeline

• Timeline is well communicated.

• Cycle is long enough to minimize PRL churn.

• Cycle is short enough to propagate important changes as soon as possible.

• PRLs are released on a quarterly cycle.

Distribution

Release

FieldTest

PRLProduction

ChangeAnalysis

SourceData

InternalTest

4-6 weeks

3 weeks

3-5 weeks

1 week

Process Timeline

For a smooth PRL process, make sure to communicate the timeline to all interested parties. The process cycle must be short enough to propagate important changes as soon as possible, yet long enough to ensure a timely and successful PRL release.

Often carriers find that production can be done fairly quickly but coordinating test resources takes more time, especially for field testing and verification.

The slide shows an example process that results in a PRL release on a quarterly cycle. All stages up to and including internal test take four weeks; the field test stage takes an additional four to six weeks. The release and distribution phases are really a function of the number of affected handsets and the capabilities in the network to distribute the PRLs.

Another major factor in the process may be the number of discrete PRLs being managed. If there are many PRLs (due to device, calling plan, technology or other specific constraints), then every PRL may not be updated at every cycle.

The best PRL process is the one that works to achieve the best available quality with the resources available. Resource constraints may mean that, although the PRL cycle runs quarterly, only half the PRLs are part of any one cycle; which may result in a six-monthly update cycle (subject to the compromises discussed earlier).



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Section 4-13


PRL Process – Section Review

1. What is the impact of a poorly designed PRL on customers?

2. What are the stages that comprise the PRL process?

3. When analyzing changes to source data, what are some key considerations?

4. What part of the PRL process typically consumes the most time?

5. What are the ramifications of choosing a PRL process cycle that is too long?

6. What if the cycle is too short?

Review1. Poorly designed PRLs may cause customers to perceive the network as having poor coverage or

unreliable service.2. The stages of the PRL process are:

Source Data ManagementChange AnalysisProductionTestingReleaseDistribution

3. Key considerations when analyzing changes to source data include:Do the changes affect any released or in-development PRLs?What are the impacts of the changes?When would it be feasible to absorb the changes?

4. With internal testing, field testing, coordination of test resources, etc., testing typically does (and should) consume the most time in the PRL process cycle.

5. If the PRL process cycle is too long, important changes may not be propagated to users in a timely manner.

6. If the PRL process cycle is too short, it may result in PRL churn, excessive PRL maintenance overhead, and potentially inadequate testing to ensure PRL quality.



80-W0902-1 Rev C


Comments/Notes


PRL Technical Workshop 80-W0902-1 Rev CSection 5: PRL Design




Section 5-1Section 5: PRL Design

5SECTION

PRL Design

Notes






Section 5-2Section Learning Objectives

Describe PRL Device Constraints.Explain and define PRL Policy Constraints.Define a Coverage Plan.Explain how to design preferences in the PRL.List the considerations for GEO Design.Define the information needed to write a PRL.Describe how to handle change analysis for a PRL.List the tools available for PRL development.

Notes






Section 5-3PRL Constraints

PRL Production requires understanding the constraints of the world in which you live.

• PRLs require design.• Design must be performed within a set of constraints.

PRL Constraints• Policy constraints:

– Implementation guidelines and strategy for their PRL. • Device constraints:

– The mobile device landscape for which PRLs must be designed and delivered.

PRL Production

This section begins with a discussion on understanding the constraints within which a PRL can be produced. This is likely one of the most important aspects of PRL design and production.

PRLs require design, and this design often must be performed within a set of constraints.

PRL Constraints

Normally, anything that requires design means that some design decisions have to made. Design decisions are often subject to some real world constraints. The design of a PRL is no different. There are two major constraint areas that PRL designers need to understand before beginning any work:

Policy constraintsDevice constraints

Policy constraints are the guidelines set in place whereby the operator defines the implementation guidelines and strategy for their PRL. Policy constraints not only define how PRL Properties will be set but also structure the coverage plan to be implemented by the designer.

Device constraints are a way of expressing the mobile device landscape for which PRLs must be designed and delivered.






Section 5-4Device Constraints

CDMA devices may support different features.

Many aspects characterize a device. PRL-related aspects include the following:

• Band Class (frequency) constraints.

• System technology constraints.

• Software version capability constraints.

• Physical memory constraints.

Device ConstraintsIn CDMA no two devices are ever created equal and often different devices can support different features. While there are many aspects of a device that can characterize it, this section is concerned only with those that relate to the PRL or its use. Device constraints may be categorized as:

Band Class (frequency) constraintsSystem technology constraintsSoftware version capability constraintsPhysical memory constraints

Band Class SupportSome devices are single band and support only one Band Class, for example, 0, 1, 5, etc. Others are dual band and can support both Band Class 0 and 1. Generally this should not become a constraint because system selection software normally ignores any acquisition records for a Band Class that it does not support (subject to any limitations on invalid channels—see below). However, this may be a chosen constraint to help mitigate other constraints, such as memory map limitations. Invalid ChannelsSome mobile devices may consider the U.S. guard-bands as invalid CDMA channels. Some carriers outside the U.S. may offer service in these channels and list them in their Technical Data Sheets. It is important to understand any device’s behavior when a channel that is considered invalid is present in the PRL. In some cases, the behavior may require that no invalid channels be permitted in the PRL of a particular device.Technology SupportNot all devices have support for AMPS analog cellular service. Some CDMA devices may not support all CDMA services. Some older devices may not support 1X/IS-95 and only be capable of IS-95, although these are becoming less common. Other CDMA devices that do support 1X/IS-95 may not support packet data services. Devices such as PC data cards may not have voice service support. 1xEV-DO PC data cards may be data only, while 1xEV-DO handset devices support voice and data. The constraining factors here are the supported PRL version and the presence of acquisition and system record entries that are unusable by the device. This constraint normally becomes a factor only when it is used to alleviate memory map constraints.






Section 5-5Device Constraints (continued)

Physical Memory constraints• Memory map defines the amount of space allocated to store the PRL.

• Typical memory map for PRL ranges from 1 KB, 4 KB, 6 KB, and 8 KB.

• NVRAM:– A PRL is loaded into non-volatile (NV) memory. The memory can be located in the device’s

NV-RAM or in R-UIM. – Maybe (should be) part of the operator’s handset requirements specifications.– NV-RAM memory maps are generally not changeable in the device.

• RUIM (Removable User Identity Module) smart card.

• RUIM memory maps are specified by the operator to the smart-card vendor.

– Subject to card and network support, the memory map can be modified once in service.

Documenting DeviceConstraints

D e v ice M o d e l B a n d -c la ss T e ch n o lo g y

1 x M a n u fa c tu re r M o d e l # S W V e r 0 1

V o ice D a taA M P S D O

In va lid C h a n n e ls M e m o ry

M a p -P R L .

Available PRL Memory

A PRL is loaded into non-volatile (NV) memory. The memory can be located in the device’s NV-RAM or in an RUIM (Removable User Identity Module) smart card. Both have a memory map definition and part of that definition is the amount of space allocated to store the PRL. Typical allocations in the memory map for PRL range from 1 KB, 4 KB, 6 KB, and 8 KB.

In the case of NV-RAM, the memory map may have been part of the operator’s handset requirements specifications or it may simply be the manufacturer’s default. NV-RAM memory maps, once defined, are generally not changeable in the device. RUIM memory maps are generally specified by the operator to the smart-card vendor and, subject to card and network support, the memory map can be modified once in service.

This is a hard constraint and the one that operators most often have to plan around. PRLs must be designed to fit into the space available. Adding roaming partners that have a significant number of SIDs can quickly cause a PRL to reach its allocation limit.

Documenting Device Constraints

The device constraints should be known to the PRL designer and form part of the information set used to build a PRL. It may be convenient for the PRL designer to use a simple tracking sheet for devices, such as that shown in the table above.






Section 5-6Some Potential Device Constraints

• Multi-Mode CDMA/GSM• 1X Data Cards – data only service• EV-DO Data Cards – data only service• EV-DO Handsets – voice and Data

Other Device Types to consider

• Specific Manufacturer devices only• Band Class 0 only• CDMA only, No Analog

Device Type 3

• Generic• Dual Band, Band Class 0, and Band Class 1• CDMA only, No Analog

Device Type 2

• Generic• Band Class 0 only• CDMA only, No Analog

Device Type 1

Notes






Section 5-7Policy Constraints

Policy Constraints – Guidelines an operator chooses to enforce across all PRL development. Policy Constraints can include the following:

• PRL Properties Policy• Support System Constraints• Mitigation Constraints• Use of Wildcards• Geo Definition Policy• Prohibited/Negative Systems Placement Policy• Use of SIDs in Multiple GEOs

Policy Constraints

Policy constraints are guidelines an operator chooses to enforce across all PRL development. These policies can be as basic as the PRL properties to the implementation of the coverage plan and application of preferences accordingly to the policy on addressing other (device) constraints.

PRL Properties Policy

The PRL properties that must be defined are the PRL preference type and the PRL identity. The PRL preference type determines whether or not the handset is permitted to use systems other than those described by the PRL.

In all cases, the PRL is network configuration data that happens to be distributed in the handset. As such, it must be identifiable for the purposes of version control and troubleshooting. It is normal for a naming policy to be in place to structure the PRL ID for this purpose. Generally, a policy on numbering is implemented. Whether a PRL is open or closed varies from operator to operator.

Support System Constraints

PRL distribution is an important factor in any network. Where automatic distribution over-the-air is deployed, this functionality is delivered by a number of operational support systems in the network infrastructure. Depending on the OTA system implementations or some other related system issues, constraints can be imposed, which can include the following:

Size limitations on the PRLs managed by the platformsNumber of PRLs that can be managed by the platformsNumber of devices that can be managed by the platformsPRL revision levels (IS-683-A, B, or C, etc.) that can be supported






Section 5-8Mitigation Constraints

Policies designed and established to directly mitigate or work around particular device or network constraints. Examples include:

Issue addressedMitigation

Overcome the constraints of the support systems that manage and distribute PRLs.Support System Constraints.

Overcome available PRL memory constraint. Limit Number of Roaming partners.

Overcome available PRL memory constraint. Defines PRLs by region, such as SE Asia, Americas etc. (Can only be supported if there is no single PRL constraint.)

Global Segmentation of Roaming Markets.

Overcome limited memory map allocation for PRLs. Maximum size limit on PRL.

Overcome limitations of available resources or support system capabilities. Single PRL support.

Mitigation Constraints

Mitigation constraints can be understood to be those policies designed and established to directly mitigate or work around particular device or network constraints, such as hard memory limitations. The following are examples of mitigation constraints:

Single PRL support – A constraint usually imposed to mitigate the limitations of available resources or support system capabilities. It means that an operator chooses to implement a single PRL for all devices—and that PRL must be compatible with all devices.Maximum size limit on PRL – A constraint imposed to mitigate the situation of limited memory map allocation for PRLs. Often, an operator has multiple deployed devices that have varying memory capacity for PRL. The operator may choose to limit the maximum size of the PRL to a lowest common denominator size.Global Segmentation of Roaming Markets – Another way to mitigate the available PRL memory constraint but can only be supported if there is no single PRL constraint in effect. This effectively creates a number of PRLs of home plus a subset of roaming partners. The subset is defined by region, such as SE Asia, Americas, etc.Number of Roaming Partners – Another way to mitigate the Available PRL Memory constraint is to impose a constraint that limits the number of roaming partners that can be included in a PRL.Support System Constraints – Imposing limitations on the size and number of PRLs or on how many device variants can be supported may be a way of mitigating the constraints of the support systems in place that are used to manage and distribute PRLs.






Section 5-9Coverage Plan

The coverage plan describes the following:

• Roaming partners • Areas where coverage is available • Technologies available in those areas• Where multiple partners exist in an area, the relative

preferences (priority) of those operators’ networks

The PRL is the implementation of the coverage plan.

Coverage Plan

The PRL is, above all else, the implementation of the coverage plan of the operator. The coverage plan describes the following:

Roaming partners Areas where coverage is available Technologies available in those areasWhere multiple partners exist in an area, the relative preferences (priority) of those operators’ networks

PRL production depends on having access to this information to design GEOs appropriately and place system records in the system table correctly.






Section 5-10Coverage Plan in the PRL

• PRL preferences are the enforcement of coverage plans.• Preference policy should be understood and documented. • The coverage plan may yield preference policies such as:

– Roaming partners all Equally Preferred– Preferences based on Carriers (not Location) based on Roaming

Agreements and/or services offered– Different Carrier Preferences in different GEOs; preferences can vary

across GEOs

• Developer must be guided when multiple partners exist.– Which is most preferred (usually based on commercial agreements)?– Different coverage footprints– Band Class and technology, etc.– How much of the partner network is to be used as part of the roaming

footprint

Partner Preferences in a PRL

The setting of preferences in the PRL is the enforcement of policies in the handset and, effectively, the programming of system selection with your network’s policies.

The coverage plan may have suggested policies such as the following:

Roaming Partners all Equally Preferred

Preferences based on Carriers (not Location) based on Roaming Agreements and/or services offered

Different Carrier Preferences in different GEOs; preferences can vary across GEOs

Preferences only apply within the scope of a GEO. Preference is established using the PRIORITY field of the system record. A device served by a less preferred system has battery life impacts and may miss pages while searching for other systems.

When dealing with roaming partners, the PRL must implement the policy that describes the desired market coverage, e.g., total, major city areas, and so on. In situations where more than one roaming partner exists in a particular market, the PRL developer must be guided by policy as to which partner is most preferred. Another important consideration is often how much of the partner network to be used as part of the roaming footprint.

Partner preference policy should recorded so that there is traceability in the design of the PRL and subsequent updates maintain the same policy.

How a Partner is Given Priority in the PRL

Preferences apply only within the scope of a GEO. Preference is established using the PRIORITY field of the system record. A device served by a less preferred system has battery life impacts and may miss pages while searching for other systems.






Section 5-11Partner Priority in the PRL

• Preferences only apply within the scope of a GEO. • Preference is established using the PRIORITY field of

the system record. • A device served by a less preferred system:

– Will search more often (battery life impacts)– May miss pages while searching for other systems

Type of Preference

Preferential treatment based on services offeredPriority Preference based on TechnologyVarying Preferences across GEOs

• All partners have equal preference• Ordering is not important

Roaming Partners all Equally Preferred

• Each partner has a different priority• Ordering is important

Priority Preference based on Roaming Partner

Priority Preference Based on Roaming Partner Where two partners exist, which one is preferred? Policies, in general, identify preferences based on roaming partners. Often this policy reflects a preference based on Roaming Agreements. Ordering is important; the most preferred operator’s systems are listed first. Carrier A may be a more preferred than Carrier B, i.e., Carrier A markets would have HIGHER Priority than Carrier B markets and Carrier A markets within the same GEO should have EQUAL Priority. Carrier B markets within the same GEO should have EQUAL Priority. Reselection exits occur when served by a less preferred Carrier B system.Priority Preference Based on TechnologyClearly there are some cases where this may not apply. The roaming experience is important and if the most preferred roaming partner has a lot of analog service this experience may be short lived, due to battery life issues. It is a good idea to have a clear guideline about which technology is preferred. It should be clear to the PRL developer whether partner or technology selection is more important.Varying Preferences Across GEOsIf inconsistencies start to appear for different regions in the same country when applying these criteria, that is an indication that one GEO per country may not be sufficient; for example, one carrier could be the more preferred carrier in the southwest while another could be the more preferred in the northeast. In such cases, extra care is required to ensure that the right priorities are established in each GEO.Roaming Partners all Equally PreferredPotentially, all roaming partners could have equal preference (i.e., PRIORITY = SAME in System table). In this case the ordering is not importantPreferential Treatment Based on Services OfferedIt may be that the policy describes a selection of a partner based on the services available to the roamer, for example, access to 1X/IS-95 or 1xEV-DO packet data services, access to location based services, access to IMS or picture messaging services, or access to Push-To-Talk services. If the coverage plan policies have been developed in this way, the most preferred systems will be grouped not by operator but by “service offering.” This is viable, but extra care must be taken to ensure that reselection exits are not too frequent.






Section 5-12Policy Constraints – PRL Structure

Guidelines on how a PRL will be structured.

• Use of Wildcards

• Geo Definition Policy

• Prohibited/Negative Systems Placement Policy

• Use of SIDs in Multiple GEOs

Use of Wildcards

PRL policy should define if SID wildcards are permitted in a PRL and under what circumstances; also, if NIDs are to be used in the PRL for system selection. The use of a NID costs an extra 16 bits in the system record and may affect any memory constraint.The level of partner network detail is further increased.

Geo Definition Policy

The coverage plan does not describe how GEOs are to be defined. There may be a policy guide on GEOs definition. Minimally it should require a description of each GEO and the rationale behind its definition. Recommendation: One GEO per country for roaming markets.

Prohibited/Negative Systems Placement Policy

The placement of negative systems in the system table can vary. In some cases a policy can dictate that all negative systems areplaced in their own GEO or a combined GEO. Maintainability is increased if negative systems appear at the bottom of their appropriate GEO and it also ensures that the frequencies of preferred systems of the GEO are immediately scanned.

Policy of the Use of SIDs in Multiple GEOs

Often toward the border of coverage, operators find that a SID that was least preferred in the home area becomes the most preferred as home coverage fades and roaming partner coverage takes over. This border coverage condition causes operators to consider use of the same SID in more than one GEO. This may mean that:

Each instance is unique as they refer to an acquisition record of different technologies (AMPS, CDMA, etc.)Each instance is unique as they refer to different acquisition records of different Band Class (0, 1, etc.)Two or more instances are indiscernible—referred to as multi-GEO SIDs. Instances of the same SID in different GEOs are indistinguishable when they refer to the same acquisition record, or to different records of the same Band Class.

When instances of a SID, NID pair are indiscernible, they are subject to the formation of a composite GEO. A composite GEO is formed from the GEOs that contain the common instance, and affect subsequent system selection. This is not necessarily an undesirable behavior. It is good to establish a policy to guide its use.






Section 5-13Design Aspects to Consider

• Representing other carriers’ networks in my PRL– This does not mean including the carrier’s PRL verbatim.– Generally, GEOs and preferences are different.

• Geographical areas – These should be defined carefully.– Small geographic areas are good. Depending on the

manufacturer, mobiles can handle 50 or 100 areas.

• Preferences in a PRL • Coexisting IS-95 and CDMA2000 1X systems• Consolidated SIDs • Border coverage issues

Representing Other Carriers’ Networks in My PRLWhen dealing with a new roaming partner with a complicated network in terms of SIDs, channels or coverage, there is the great temptation to obtain a copy of their PRL and insert it into an existing PRL. This verbatim inclusion is dangerous for the following reasons:

GEOs are different.Coverage Plans are different.PRL policies are different.Roaming partners are different.

Coexisting IS-95 and CDMA2000 1X SystemsThe PRL for 1X mobile stations should make a 1X system preferable over an IS-95 system in the same GEO. Depending on implementation, two systems may have the same or different SID and NID. 1X and IS-95 systems should be separate records in the system table and be in the same geographic region. With this implementation, even though the device acquires an IS-95 system, it is directed to acquire the 1X system in the same GEO. Consolidated SIDs SID consolidation has become prevalent. SID consolidation is when an area described by multiple SIDs is reassigned with a single SID. Operators should carefully consider the effects of SID consolidation on partner PRL design. A general guideline here may be to ensure that where a SID is consolidated into a larger grouping that the old SID is replaced by a NID within the new SID. This is particularly important in the case where more than one CDMA operator exists in the described coverage area. The danger of not doing this can force a decision between leaving a coverage hole or selecting a particular roaming partner over a wider area than is needed or desired. Border Coverage IssuesEvery coverage area has its border. Partner SIDs that provide service in another GEO can seep into the coverage area of the home system at the borders. This border coverage condition can be addressed with the use of multi-GEO SIDs—subject to the policies in place.






Section 5-14GEO Design

Geographic Region Definition must address the following:• Logical separation of areas based upon:

– Coverage– Roaming Rates– Preferences

• Maintainability and Easy Readability

ConsProsNo. of GEOs

• Requires more design• Careful GEO definition

• Easy to read• Easier to maintain – Localization

of Change• More efficient scanning and

reselection

More GEOs

• Difficult to read• Difficult to maintain• More disparate areas grouped

together – inefficient searching• More reselection

• Easier to write initially• Less design effort

Fewer GEOs

Logical Separation of Areas Based Upon Coverage

The prime function of the GEO is to group service areas into a larger logical areas. Every PRL must have at least one GEO.

Care should be taken in designing GEOs such that they represent logical separation of areas based upon coverage. Small GEOs are good and easily maintained.

What’s the footprint of the roaming service? Could be national, regional in nature based on landmass covered. Example: U.S. Northeast, Midwest, Northwest, Southwest, Southeast, Mexico, Western Canada, Eastern Canada.Are there competing operators in the coverage footprint?

List only systems of operators with roaming agreements. A partner of your Roaming Partner is not necessarily your Roaming Partner, too.

Are there any coverage holes? Have all systems within the coverage been listed? For a ‘closed’PRL (Preferred_Only=True), service is not provided on any system that is not listed in the PRL.






Section 5-15Information for PRL Production

Requires the collection information to build the PRL, including:• PRL Device and Policy Constraints• Coverage plan• Derived information• Partner information

Roaming partner delivered data• Many different formats• Varying levels of information• Contains much more than is needed just for PRLs

– Frequency Band and channel– Broadcast SID and NID– Market identification information

Organization of data• Controlling the source

– Configuration management as for any operational data• Consider building derived sources

– Internal format of TDS for PRL– Coverage and Preference Plan

Information Required PRL Production Any PRL production requires the collection of all the information that is to be used to build the PRL. This information includes:

PRL device and policy constraintsCoverage planRoaming Partner delivered dataDerived information

One way to view PRL production is the combining of much information from multiple sources, used to construct a PRL in a human understandable form. That form must then be represented in a binary form for use by the mobile device. As roaming partners, devices, coverage and network capabilities are added, that information changes. The process section highlighted the need for careful version control of

the production PRLs which versions of production PRLs are deployed where all the sub-components (source data elements) that are used to arrive at a PRL

Without traceability of source data, maintaining PRLs is an arduous task resulting in a longer time to get production PRLs in the market and potentially adversely affect the roaming revenue stream.Record KeepingThings change. Policies and device constraints may not change frequently. New roaming partners extend coverage. Existing roaming partners report changes to the network information. Some sort of version control process ensures that future change (in either the production PRLs or personnel that produce them) is, at least, manageable. How this management is achieved is the choice of the operator, and can range from something as simple as rigorous manual logs (for record keeping and cataloging) to a commercially available configuration management system. This is a situation where having a process is much more important than any automation and tools. A bad system automated just makes bad things happen faster.






Section 5-16Information from a Roaming Partner

PRL Section Technical Data Sheet (TDS)

• Broadcast MCC and MNC• Broadcast SIDs and NIDs (if applicable) • Band Class • Blocks or bands and • Channels• Market identification information

Information from a Roaming Partner?

Operators exchange information to enable roaming in a vehicle known as the Technical Data Sheet (or TDS). The TDS contains many information elements relevant to many more aspects of network interoperation than just the PRL. The TDS covers many aspects of network including HLRs, Billing IDs, MSC-IDs, point codes, TLDNs, etc., but for the PRL the key elements are those that describe the network’s service areas in terms of the following:

Broadcast MCC and MNCBroadcast SIDs and NIDs (if applicable) Band Class Blocks or bands and ChannelsMarket identification information

Periodic verification on information to and from roaming partners can be limited to technical data review or can include test calls and test bills.






Section 5-17Change Analysis

Each change in source data starts an analysis workflow.

• Identification of change– TDS often have an update detail note.

• Identification of affected downstream items– Derived sources– PRLs

• Assessment of severity of change– Not every change is a high priority– Treated like software fixes– Work assessed and programmed in with other PRL activity– PRL CYCLE


When a change happens, you must be able to assess the following:Does this change affect any of the currently released or in-development PRLs?If so, which ones?If so, is this a change I need to, or can afford to, absorb at this time?If so, how and when should this change be propagated to the PRL?

These questions, in essence, describe the functions of change analysis for the PRL process.

This requires the examination of new data to identify any impacted released data. Once the affected PRLs are identified, the analysis should extend to figuring out the scope of the change, and, how it should be included. There can be many factors that affect the priority of an identified change, such as:

Resources available to effect the changeRevenue (or other) impacts of [not doing] the changeRelative importance of the affected area to the customer baseWhen in the PRL process new data arrives, i.e., cut-off or data-freeze dates

All of the factors discussed above are considered, then the result is described in the change details and/or work orders for PRL production.






Section 5-18PRL Design – System Table

Start with System Table

• Data source needed: TDS and commercial data

• GEO definition

• List only SIDs of roaming partners

• Determine priority within a GEO

• List negative systems if any

• Ensure complete coverage within GEO

Notes






Section 5-19PRL Design – Acquisition Table

Generate Acquisition Table• Data source needed: TDS• Acquisition Record for each System Table Entry

– Link Acquisition Records with System table entries

• Delete duplicate Acquisition Records• Determine ordering of the Acquisition Records

– Scan Lists are based on Acquisition Table (Left Right, Top Bottom

• Optimize for easier maintainability and readability– Individual channels vs. Blocks– Keep it Simple– Size based on IS-683A

• Can use sample PRLs provided by partners as sanity check

Notes






Section 5-20PRL Tools – The PRL Editor

PRL Editors• As an Editor

– Often where problems occur– Akin to writing in assembly– Limited readability– Limited editing facilities

Often no undo featureSimple mistakes can cause major rework

• As a Compiler– Can import a text file of the

right format– Write out the PRL in binary

format– Source code is protected

elsewhere

PRL Editors

Most handset manufacturers provide some form of PRL editor tool. These tools can be problematic when large PRLs are involved. These are some of the problems that can be encountered:

Single Line by Line EntryNo or limited undo functionsLimited cut, copy, and pasteNowhere to add additional information such as carrier name, market name, or design decisionsRestricted to binary format for input and output files

The discipline to save frequently and track major edits as they are complete is often the price to pay for this environment.






Section 5-21PRL Tools – Spreadsheet

Spreadsheet Editing• Richer Information format• More readable• Edits are clearer• Richer editing environment• Supplementary information can be

present– Market information– Carrier information– Rationale for record

Macros• Macros compile to text form on separate

worksheet• Compiled form worksheet saved as text

Compilation• In cases where the OTA system does not

accept text form PRLs• Text form read by PRL editor• Binary form output by PRL editor

Production

Source Data

Released Data

Change Details

Pre-release Data

Rich Format Spreadsheet

Macros

Text Format Spreadsheet

PRL Editor Format Text File

PRL Editor

Compiled Binary form PRL

Spreadsheet Production

Understanding the limitations of the PRL editor is all well and good, but many people with PRL responsibilities find themselves in the situation of OTA systems not yet in place, stringent time pressures, and only the PRL editors to work with.

The good news is that the PRL editor limitations can be mitigated to some extent. In general, spreadsheet applications provide much richer editing environments. In addition to the columns needed for the PRL, developers can have all sorts of supplementary information present, such as the region, market, carrier name, TDS cross-reference, and whatever else their process requires.

Using a spreadsheet is great but if starting with a binary PRL, how does the PRL get into the spreadsheet and once the editing and construction are all done how does it get into the binary form again? There are basically three options here:

Using the PRL Editor as a compilerTools that transparently handle PRLs negating the need for a PRL editor (e.g., PRL Presto)Working with text-only PRLs






Section 5-22

PRL Edition(PRESTO)

PRL Testing(PREDICT)

TDS managementPRL Policy Design

(PREDICATE)

PRL Tool Suite – An Excel Add-in

• PRL maintenance is complex: PRESTO as a Excel based Editor

• TDS maintenance is complex: PREDICATE as an Organizer

• PRL Building is obscure: PREDICATE as a new PRL Designer

• System Selection is confusing : PREDICT as the phone simulator for PRL tracing

TDS documents

binary PRL file

10101001101111110110111000011110011

PRL Toolbar Suite

Motivation

PRL maintenance is complex

– Actions from the most abstract layer (contract agreements with other carriers) to a complex computer/headset technical field (binary file) are required.

TDS maintenance is complex

– Current Datasheets are often incomplete and difficult to track; PREDICATE provides a geographical organization for TDS and updates!!

PRL building is obscure

– Using the data coming directly from the TDS read by PREDICATE, we have available a tool for PRL Policy Design, which leads us to a PRL; easy and errorless.

System selection is confusing

– PREDICT provides PRL developers a first testing environment for their PRL design before going to field test. The code inside PREDICT is the same code that is given to phone manufacturers.






Section 5-23PRESTO

PRESTO (PRL Toolbar Suite)

RL Editor (QPST)

binary PRL file

10101001101111110110111000011110011

Modified binary PRL file

10101001101111110110111111110010011

PRESTO’s FunctionalityRead and Write PRL files to and from ExcelGive us the size of each Acquisition Record, System Record, and PRL fileEditing primitive functions:

– Over Acquisition recordsInsertMoveDelete

– Over System RecordsInsertDelete

Special edition functions– Remove non-referenced Acquisition Records– Redirect System Records

Customizable labelsDynamic validation






Section 5-24PRL Auditing

Verification of PRL by static analysis

System Table• Verification ofmarkets to SIDs and channels• Identification of missing data

Acquisition Table• Identification of unreferenced channels

Auditor Tools

The use of auditing tools is an excellent way to verify that the PRL contains valid information. Auditing tools provide a form of static testing. Generally an auditor tool performs the following tasks.

Verify that every entry in the PRL is described in technical data sheets and that the description is correct.

Identify any systems in the PRL that are not described in the technical data.

Identify any channels that are not described for a particular system in the technical data.

Identify all unreferenced channels in the acquisition table.

PREDICATE is a utility from QUALCOMM that performs this type of static auditing. Auditing is difficult for today’s CDMA PRL developers because of the wide range of formats in use for the exchange of Technical Data Sheets.






Section 5-25PRL PREDICATE

PRESTO (PRL Toolbar Suite)

PREDICATE

PRL InformationTDS information

Reports

PRL Auditing

PRL Policy Creation

TDS Importing/ManagementClassify your TDS documents independently of where they are located on your hard drive.Read the heterogeneous TDS information into a homogeneous database where it can be easily managed.Manage TDS UPDATES automatically.Report TDS reading problems such as:

– incoherent values– missing information– not valid entries

PRL Policy Creation/ManagementDefine PRL Header properties.Define each one of the GEOs of your PRL.

– Add Operators and prioritize them– Add Markets– Restrict modes of operation and create priorities between them

All information comes from the previously loaded TDS (No room for mistakes).






Section 5-26PRL PREDICT

PREDICT

PRESTO

PREDICATE

PRL Data

TDS Information

Trace PRL behavior

PREDICT’s Functionality

PREDICT is a System Selection code simulator; it uses the same code that’s given to manufacturers. The simulation is carried out using RF data coming from the TDS information previously loaded with PREDICATE. That data is narrowed down by clicking in a specific globe position on the map and selecting a market for which TDS data is available.

PRL information will be read with PRESTO, which guarantees that any PRL that PRESTO can read is be available for use in PREDICT. Some more information regarding the System Selection process (which is usually hidden) is available to the PRL Tester.






Section 5-27PRL Design – Section Review

1. What is the difference between device and policy constraints?

2. What are three types of device constraints?

3. What is an example of a PRL properties policy?

4. Which provides more efficient scanning and less reselection, a PRL with fewer or more GEOs? Why?

5. Which is easier to maintain, a PRL with fewer or more GEOs? Why?

6. How is the TDS used in PRL design?

7. What are the three components in the PRL Toolbar Suite?

Review

1. Device constraints deal with limiting characteristics of devices on which PRLs are loaded. Policy constraints deal with an operator’s guidelines and strategy for developing and supporting PRLs.

2. Types of device constraints include:System technologies supported (e.g., AMPS?) Band Classes/frequencies supported (e.g., 800 MHz)Whether the device considers certain channels to be invalidWhether newer PRL versions are supported (e.g., IS-683-C)Maximum memory available for PRL storage

3. PRL properties policies include:Whether PRLs will be open or closed (i.e., Preferred_Only property) Consistent method for identifying PRLs (i.e., PRL_ID property)What default roaming indicator to use for undefined systems acquired by an open PRL

4. Using more GEOs in a PRL provides more efficient scanning and less reselection because each GEO contains a smaller number of systems and disparate areas.

5. A PRL with more GEOs is easier to maintain because changes are more localized.6. Among the information contained in a TDS is the system ID (SID/NID, MCC/MNC) and air interface information (Band

Classes, blocks/bands, channels) for each coverage market. This information is required to create PRL system and acquisition records.

7. The PRL Toolbar Suite includes three components:PRESTO – PRL editingPREDICATE – PRL auditing against TDS dataPREDICT – device simulation using PRL and TDS data




Comments/Notes


PRL Technical WorkshopSection 6: PRL Design Checks

80-W0902-1 Rev C



Section 6-1


Section 6:PRL Design Checks

6SECTION

PRL Design Checks

Notes



80-W0902-1 Rev C



Section 6-2



List PRL structure & design issues.Explain potential reselection exits.Define distant regions in the same GEO.Discuss coverage holes in GEOs.Explain the consequences if AMPS systems are present.Explain the consequences if unlisted SIDs are present.Discuss inconsistent preferences within GEOs.Explain what to do with duplicate system records.

Notes



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Section 6-3


PRL Design Issues

• Potential Reselection Exits• Distant Regions in Same GEO• Coverage Holes in GEOs• Presence of AMPS Systems• Presence of Unlisted SIDs• Inconsistent Preferences within GEOs• Duplicate System Records

Notes



80-W0902-1 Rev C



Section 6-4


Potential Reselection Exits

• SIDs from:– Same carrier – Same GEO – Differing priorities

• Geographically disparate SIDs in the same GEO with differing priority.– This will cause Reselection exits in the GEO for:

All except the most preferred SIDsA device would keep attempting to acquire one system in a remote market with 0% chance of acquiring the systems sought.

• If a carrier is a more preferred:– Only the last carrier’s SID in the GEO should be listed as “MORE.”– Other SIDs should be listed as "SAME.”

Potential Reselection Exits

The combination of technology and preference order specified in a GEO can implicitly introduce reselection exits. Recall that in some implementations, service on an AMPS system can cause more frequent attempts to seek better service.

Also, a poorly designed GEO can have the side effect of continually exiting normal service to perform reselection, even in cases where there may be no better service available. This can happen in a GEO where attempts to further refine the GEO with geographical priorities are established in a single GEO.

Example1: A PRL that has a GEO of a roaming market (say the U.S.A.) and the most preferred system as the most frequented market (say Miami) will force the device into reselection anywhere outside of the most preferred coverage even though there is little or no likelihood that the most preferred system can be detected.Example2: A PRL has a GEO with two partners providing coverage in the same market. Eerroneously marking all systems from the same carrier as “MORE” instead of “SAME”has the effect of causing reselection exits to look for the first listed system in the GEO.

A GEO should be regarded as the lowest level of geographic granularity. If more granularity is needed, the GEO should be split into more GEOs. Priorities should be limited to establishing technology (Band-class) and roaming partner priorities.



80-W0902-1 Rev C



Section 6-5


Coverage Holes in GEOs

• Not all SIDs of a Carrier are represented in the GEOs.

• If PREF_ONLY is enabled in the PRL, service will not be provided in these markets.

• Check TDS for omissions and understand any omission.

• Add any missing SIDs to the respective GEOs for complete coverage.

Coverage Holes in GEOs

When all of the SIDs of a carrier are not represented in the PRL, and if the PRL is a closed PRL (PREF_ONLY=FALSE), then potentially service will not be provided in those missing markets.



80-W0902-1 Rev C



Section 6-6


Presence of AMPS Systems

• AMPS systems listed in the PRL are sometimes erroneously linked to Standard CDMA Acquisition Channels.

• If AMPS service is to be provided, link these systems to appropriate Analog Standard Channels/Blocks.

• Use of CDMA Preferred Acquisition records can cause inadvertent selection of AMPS systems.

Inadvertent Presence of AMPS Systems

Use of the CDMA Preferred acquisition record indicates that a device on this band should first look for CDMA, and then, if no CDMA Pilot is found, look for AMPS service before advancing to the next acquisition record.

If this is the desired behavior, there is no problem. However, if AMPS systems should not be acquired in roaming markets (e.g., in cases of fraud risks), then the PRL should be written to explicitly select CDMA and AMPS, in the appropriate preference order.



80-W0902-1 Rev C



Section 6-7


Presence of Unlisted SIDs

• Listing SIDs in the System Table that are not listed in any TDS is dangerous.

• If no roaming agreements exist, then:– The handset acquires one of these SIDs.

– ANSI-41 registration fails.

– If serving network does not send a 'RegistrationRejectOrder, thedevice camps on a network with no service.

• List systems only if TDS data exists.

Inclusion of SIDs not Listed in Technical Data Sheets

When SIDs are listed in the PRL but not in the TDS, this could have the following effect: the device may select a system for which no roaming agreement is in place and thus the device will fail to successfully register on that system. Unless the system sends the mobile device a Registration Reject Order, which many systems do not, the device remains on a system that cannot provide service.

Problems of Acquiring a SID on a Non-Partner Network

If the handset acquires a SID that exists in the PRL, but for which no roaming agreement is in place, in all likelihood the registration attempt will not succeed. If that serving network does not support the sending of a Registration Reject Order, the handset is unaware of the unsuccessful attempt and remains camped on an unusable network.



80-W0902-1 Rev C



Section 6-8


Inconsistent Preferences within GEOs

• Inconsistent preferences within GEOs should be well understood.– Some carrier A SIDs are “MORE” Preferred over

carrier B SIDs, while other carrier B SIDs are NOT.

• This attempts to create SUB-GEOs.

• All markets of a specific carrier within a GEO should have EQUAL Priority/Preference.

Inconsistent Preference within GEOs

It is always worthwhile to check the consistency of preferences between technology (band-classes) and roaming partners within GEOs. Inconsistencies can mean different things:

They may be intentional and by design, in which case the established policy can be referenced. They may indicate that further geographic definition is being attempted within the GEO (see earlier). They may simply be a mistake that results in the incorrect roaming partner being selected in some GEOs. This could affect service and/or revenue.

Example

In a particular GEO, a PRL declares that in City Market 1, Carrier A is more preferred than Carrier B. In the same GEO an attempt is made to declare that in City Market 2, Carrier B is preferred over Carrier A. This additional geographic refinement could have the following result: while in Market 2 on Carrier B, the device will perform reselection exits to acquire the Carrier A system in Market 1.



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Section 6-9


Duplicate System Records

• System records that are listed two or three times in the same GEO increase the size of the PRL.

• So… delete duplicate records.

Duplicate System Records

Having system records listed multiple times in the same GEO with the same acquisition record may have no adverse affect on system selection, but it does use up valuable real estate in the PRL. Check to ensure that the appearance of a SID more than once can be fully explained.



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Section 6-10


PRL Design Checks – Section Review

1. Scenario: FooTel operates systems across the U.S. with their biggest market being New York. GEO1 contains their New York CDMA system as most preferred and their other U.S. CDMA systems as less preferred.

a) Why would this be a problem for FooTel customers in California?

b) How should FooTel change their PRL?

2. Within a GEO, how should priorities be used?

3. What is the behavior of a CDMA Preferred acquisition record?

4. What could cause a device to camp on a network with no service?

Review

1a. Their devices will continue to try to acquire the New York system because it is most preferred even though they have no chance of acquiring it. The continual reselection attempts result in lower battery life and potential missed pages.

1b. They should make all of their CDMA systems the same priority within the GEO. They may also want to split the GEO into two or more GEOs that are smaller and more geographically localized.

2. Priorities within a GEO should only be used to establish preferences between different technologies (band classes) and roaming partners. System priorities should not be used to attempt to establish geographic preferences inside of a GEO, as this can often result in unintentional reselection exists.

3. The behavior of a CDMA Preferred acquisition record is to first look for CDMA; if CDMA is not found, then look for AMPS before advancing to the next acquisition record. Note that this behavior may result in AMPS service being selected over CDMA service (i.e., the AMPS service of a higher priority system will be selected over the CDMA service of a lower priority system).

4. Camping on a network with no service is caused by the use of a wildcard SIDs, use of an open PRL (i.e., Preferred_Only = False), or presence of a system record for an unlisted SID (i.e., SID is not in the TDS) that causes the device to acquire a non-roaming partner system. Many CDMA systems will not send a RegistrationRejectOrder to the device in this scenario.


PRL Technical WorkshopSection 7: Hybrid 1X / EV-DO PRL

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Section 7-1


Section 7:Hybrid 1X / EV-DO PRL

7SECTION

Hybrid 1X / EV-DO PRL

Notes



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Section 7-2



Define 1xEV-DO. Define a Sector & a Subnet ID.Explain the changes for IS-683C PRL.Describe the new records for EV-DO.Explain the association of 1X and DO systems.

Notes



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Section 7-3


The PRL with CDMA2000 1xEv-DO

• EV-DO requires the use of IS-683C PRLs.

• As before, the PRL specifies the following permitted items:– Frequencies

– Systems

• IS-683C:– Defines hybrid access terminal operation.

– Is an extension to IS-683A/B.

– Extended to include support for an IS-856 system record type.

– Supports the defining of associations between IS-2000 systems and IS-856 systems.

What is 1xEV-DO?

CDMA2000 1xEV-DO is an evolution of CDMA2000 and an approved 3G standard for fixed, portable, and mobile applications. CDMA2000 1xEV-DO is Data-Optimized, providing a peak forward data rate of 2.4 Mbps for Revision 0 and 3.1 Mbps for Revision A, and peak reverse rates of 153 kbps and 1.8 Mbps for Revision 0 and A, respectively. IS-856 describes the operation of CDMA2000 1xEV-DO systems.

Understanding some of the basics of an 1xEV-DO network and the mode of operation of the 1xEV-DO device (often called the Access Terminal or AT) is necessary to understand how to properly construct a PRL and how that PRL is used by the device. Necessary elements are:

The Sector-ID and its use in 1xEV-DO systemsThe subnet ID and its use in the PRL and how it relates to Sector IDHybrid Mode 1xEV-DO operation



80-W0902-1 Rev C



Section 7-4


IS-683C PRL

IS-683C:• New PRL format that adds support for IS-856 (1xEV-DO) systems.

• Includes new:– Acquisition Record in Acquisition Table– System Record type in System Table for IS-856 systems

• Acquisition Table– Generic Acquisition Record for IS-2000/IS-95 and for IS-856

Specifies band class and channel number pairs-

• System Table– System record type is used to differentiate between IS-2000/IS-95 and

IS-856 systems.– In IS-856 system record type:

SID- and NID-related fields are replaced with Subnet-ID related fields.New Association fields to link IS-856 system to an IS-2000 system.

IS-683C PRL Structure

The PRL in revision C of the standard adds some new structure and meaning. It still contains the three major sections as before (properties, Acquisition Table, and System Table) but now allows for additional elements:

A new table called the common sub-net table.A new extended system record that can describe analog, 1X/IS-95 and 1xEV-DO systems.New grouping and linkage mechanisms that introduce a new level of sub-grouping of 1X/IS-95 and 1xEV-DO systems fully contained within the existing GEO grouping mechanism.New generic CDMA and 1xEV-DO acquisition records.



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Section 7-5


Sector ID in 1xEV-DO

The Sector ID of a 1xEV-DO sector is defined to be 128 bits.

• Typically 24 least significant bits uniquely identify the sector.

• 104 most significant bits identify the subnet.

• A sector belongs to subnet.

• Sector IDs should be chosen to ensure global uniqueness.

• Suggested provisioning:

– Common set of most significant bits for all sectors

– Large amount of least significant bits as a pool for sector uniqueness

The Sector ID in 1xEV-DO

The Sector ID of a 1xEV-DO sector is a name that it broadcasts to identify itself. It is defined to be 128 bits and comprises two major elements:

Sector identity part. Typically the 24 least significant bits uniquely identify the sector.Subnet identity part. Typically the 104 most significant bits identify the subnet.

A sector belongs to a subnet. One analogy that may help here is that the subnet identity part is similar to the SID in 1X/IS-95 systems, and the sector identity part is similar to a NID.

However, unlike a NID, the sector identity part should be chosen to ensure global uniqueness as opposed to the NID being unique only within the SID namespace.



80-W0902-1 Rev C



Section 7-6


Subnet ID in the 1xEV-DO PRL

• Access Terminal (AT) uses the SubnetID field in the PRL to determine whether it should stay on an acquired 1xEV-DO network.

• The SubnetID field is defined by a value and a length.

• A length of zero:– Is defined as a wildcard mask.

– Selects any 1xEV-DO system.

• When the length is non-zero:– Forms a mask on the length most significant bits of the SectorID.

– Sector ID received in the Sector Parameters message.

– If the mask matches the length most significant bits, the AT can select this 1xEV-DO system.

– If the mask does not match, the AT continues to search.

Subnet ID in 1xEV-DO

A subnet ID in the PRL is a 128-bit address value formatted according to the IPV6 protocol (not an IPV6 address). IPV6 format comprises eight 16-bit values separated by colons followed by a slash and a length value within the range 0 to 127. It is not necessary to write the leading zeros in an individual field, but there must be at least one numeral in every field, for example:

Just as a SID of zero value meant any SID in 1X, a subnet ID of /0 indicates a wildcard subnet ID and indicates any 1xEV-DO system is selectable (subject to network authorization and authentication.)

The length value indicates how much of the subnet-ID is significant. Generally 1xEV-DO systems are only specified in the PRL at the subnet-ID part (equivalent to SID-only usage in 1X); thus the length generally will be 104 bits or less.

104 bits 24 bits Bits . 16 16 16 16 16 16 16 16

Subnet ID . 0000: 0000: 0000: 0000: 0000: 0000: 01 00: 0000 /104

Can be written as . 0: 0: 0: 0: 0: 0: 100 0 /104

Subnet ID Part Sector ID



80-W0902-1 Rev C



Section 7-7


IS-683C PRL Structure

Grouping of Systems Within the Scope of a GEO

1xEV-DO systems are deployed either as adjunct or overlay networks to 1X/IS-95 networks. Detecting a 1X/IS-95 network would not necessarily reveal any information about the presence of a 1xEV-DO network. While both 1X/IS-95 and 1xEV-DO systems can be accessed independently, operational scenarios exist where a mobile device would access both.

1xEV-DO by itself brought about the need for new system record and acquisition record types; however, the need to access both types of network at the same time introduced the need to capture co-location information in the PRL. This co-location scheme can only be applied (i.e., only has meaning) within the context of a geographical area.

Common Subnet Table

A 1xEV-DO system is recognized by a [up to] 128-bit subnet identity, as opposed to the 15-bit SID for analog and 1X/IS-95 systems. The common subnet identity table provides a mechanism for Subnet-ID compression by repeating any common Subnet-ID prefix only once in this table.

This is, in effect, a table of Subnet-ID prefixes. A 1xEV-DO system record, with a common Subnet-ID prefix, would then contain only the unique least significant bits of the Subnet-ID and refer to an entry in the common subnet table for the most significant bits. The full Subnet-ID would be obtained by concatenating the prefix from the common subnet table and the least significant bits from the 1xEV-DO system record.

Although this mechanism is described in the standards and likely present in most implementations of system determination, currently most of the PRL writing tools that produce IS-683C PRLs do not perform this optimization.



80-W0902-1 Rev C



Section 7-8


IS-683C – The New Records

0:0:0:0:0:0:0:0/26

SUBNET_ID

0001

SYS_RECORD_TYPE

1

ASSOCIATION_INC

3

ASSOC_TAG

NoNo

DATA_ASSOC

PN_ASSOC

12

11

10110

Acquisition typeAcquisition Index

Acquisition Table

System Table

HRPD System

Generic Acquisition Record for HRPD (High Rate Packet Data: IS-856 systems)

Description

If set to 1, HRPD system is associated with an IS-2000 System

HRPD system and associated IS2000 System have different PNs

HRPD system and associated IS2000 System have different PDSNs

• Length of Subnet ID: 26 bits• AT will apply the mask to 26

Most Significant Bits of the Sector ID.

The PRL with 1xEV-DO

As before, the PRL still specifies the frequencies and systems that the Access Terminal is allowed to acquire. The standard has been extended to include support for an IS-856 system record type. The Preferred Roaming List format has also been extended to include support for defining associations between IS-2000 systems and IS-856 systems. These extensions to the Preferred Roaming List format are defined in the IS-683C standard.



80-W0902-1 Rev C



Section 7-9


1xEV-DO Acquisition Record

• Acquisition Type

• Band Class

• Channel

Acquisition Record Field Length (bits)

ACQ_TYPE 4

LENGTH 5

LENGTH/2 occurrences of

BAND_CLASS 5

CHAN 11

High Rate Packet Data (EV-DO) Acquisition Record

In Revision C of the standard, Generic HRPD (High Rate Packet Data) became available. The Generic HRPD acquisition record instructs the mobile device to search for 1xEV-DO service on a specific channel of a specific band-class.

Up to 16 band-class and channel pairs can be specified in one record. Generally, the order in which the channels are listed is the order in which they would be searched. This record is in the Extended Acquisition Record Format. This extended format is merely an encoding extension but would be transparent in tools such as PRL editors. The actual field names and lengths are described in the standard in its extended acquisition record format.

Acquisition Type

An editor will generally show a meaningful descriptive term for this, e.g., “HDR Generic.” In the standards, the mechanism to identify an HRPD Generic acquisition type record is by setting the actual (decimal) value of 1011 for the ACQ_TYPE field.



80-W0902-1 Rev C



Section 7-10


IS-683C System Record Structure

IS-683-C System Record

Record Type1

Acquisition Record Index

Selection Priority Indicator

Analog or 1x/IS-95 System Record

Preferred or Negative Indicator

1 of

1

1

0|1

System Identification (SID)

Roam Indicator

System Identification Part1

1Network Identification (NID)0|1

0|1

System Characterization Part1

System Association Part0|1

Sub-Net Identity

PN Association

Data Association

EV-DO System Record

1

0|1

0|1

Association Tag1

Geo Indicator1

SID Based Identifier

1 of

Subnet Based Identifier

Common Sub-Net Table Entry0|1

Pre IS683-C Structure

New IS683-C Structure

Actual Fields in record

The IS-683C System Record Structure

The new system record introduced by IS-683C (the extended system table record) can be conceptually visualized as having four parts, namely:

Record type – indicates whether the record is a Type 0 system record (analog, 1X/IS-95) or a Type 1 1xEV-DO system record.System Characterization part – identifies the GEO, preference type, selection priority, roam indicator, and the acquisition record that describes the band-class and channels for the system.System Identification part – describes the broadcast identity of the system that is to be recognized. An analog system has only a SID; a 1X/IS-95 system has a SID and optionally a NID; a 1xEV-DO system has a subnet-ID.Association part – identifies systems that are co-located (i.e., grouped together inside the GEO scope) for the purposes of hybrid operation.

In the representation shown, only the right-most nodes actually represent fields in the system table record.



80-W0902-1 Rev C



Section 7-11


1xEV-DO System Record

• System Record Type • Negative/Preferred• Geography• Priority• Acquisition Index• Roam Indicator

System Record Field Length (bits)

SYS_RECORD_TYPE 4

PREF_NEG 1

GEO 1

PRI 1

ACQ_INDEX 9

SUBNET_COMMON_INCLUDED 1

SUBNET_LSB_LENGTH 7

SUBNET_LSB SUBNET_LSB_LENGTH

SUBNET_COMMON_OFFSET 0 or 12

ROAM_IND 0 or 8

ASSOCIATION_INC 1

ASSOCIATION_TAG 0 or 8

PN_ASSOCIATION 0 or 1

DATA_ASSOCIATION 0 or 1

EVDO System Record Fields (IS-683C)

The 1xEV-DO systems that are to be permitted or prohibited are described in a system record of the system table. An editor view of the system table is shown above. The specific fields of a system record are shown in the table.

System Record Type – indicates whether the record is a 1X/IS-95 record (Type 0) or a 1xEV-DO record (Type 1). The type determines which identification scheme is used as the System Identification.Negative/Preferred – this field has the same meaning as before, except now that it applies to a 1xEV-DO system.Geography – this field has the same meaning as before, except now that it applies to a 1xEV-DO system.Priority – just as before, only a preferred 1xEV-DO system can have priority. Priority for a 1xEV-DO system is applied within the scope of systems identified as being co-located (by way of the association tag). Negative systems prohibited. The same rules (and cautions) of use apply here as before.Acquisition Index – this field is set to the index of the acquisition record that specifies the acquisition parameters for the system associated with this record. Roam Indicator – only preferred systems can have a roam indicator. For negative systems, this field is omitted.



80-W0902-1 Rev C



Section 7-12


1xEV-DO System Identification

System Record Field Length (bits)

SUBNET_COMMON_INCLUDED 1

SUBNET_LSB_LENGTH 7

SUBNET_LSB SUBNET_LSB_LENGTH

SUBNET_COMMON_OFFSET 0 or 12

System Identification PartThe type of the system record determines which type of identity may be used. For a 1xEV-DO system record (Type 1), subnet identification must apply (as opposed to SID/NID identification, which applies to 1X/IS-95 systems). The subnet ID can take two forms in the PRL. The first, and most typical, is where the full subnet identity is contained in the system record. The second form is where part of the subnet ID is in the system record together with information about how to locate the other part from a store known as the Common Subnet Table.Full Subnet in System RecordWhen the full subnet is described, all significant bits are contained in the record and no part of the of the subnet is located elsewhere. It is explicitly stated in the record that the common subnet table is not used. The following are the fields of the identification part of the Type 1 system record:

SUBNET_COMMON_INCLUDED – indicator value of 0 indicates that the Common Subnet optimization is not being used.SUBNET_LSB_LENGTH – contains the entire subnet that follows (104 in the example shown).SUBNET_LSB – the field that contains all the bits of the subnet. SUBNET_COMMON_OFFSET – omitted when SUBNET_COMMON_INCLUDED has a value of zero.

Use of the Common Subnet TableIf the most significant part of the subnet-ID is common, this can be optimized through the use of the common subnet table. This optimization is indicated by the following:

SUBNET_COMMON_INCLUDED – indicator value of 1 shows that the Common Subnet optimization is being used and that a reference to the Common Subnet Table is included.SUBNET_LSB_LENGTH – contains the length of the unique part (the least significant bits) of the subnet that follows.SUBNET_LSB – the field that contains the least significant bits of the subnet. SUBNET_COMMON_OFFSET – is the vector to the part of the Common Subnet Table that contains the most significant bits of the subnet associated with this system record (e.g., a value of zero for this field points to the beginning of the Common Subnet Table).



80-W0902-1 Rev C



Section 7-13


Association of IS-856 Systems

• Association Tag – used to link IS-856 system with IS-2000/IS-95 systems:– Association tag is an 8-bit.

– Values between 0 and 255.

– Only systems in the same GEO can be associated.

• PN Association – indicates that the IS-2000 and IS-856 systems have the same PN offset.

• Data Association – indicates that the IS-2000 and IS-856 systems are using the same PDSN.

Association Part

The presence of an association is indicated by the ASSOCIATION_INC field having a value of 1. Three associations form the association part of the system record.

The first, and most significant in use today, is the ASSOCIATION_TAG. This is an 8-bit number that names the “association set” to which this system record belongs. The set name only has meaning within the scope of a GEO. System records in the same GEO that have the same Association Tag are members of the same set. System records in different GEOs that have the same Association Tag are not members of the same set.

The other two associations, while present in the PRL, are not currently used by system selection but their description is included here for completeness:

PN association flag – identifies systems that have the same PN offset assignment (i.e., co-located). Data association flag – identifies systems that can reach the same set of PDSNs (i.e., associated).



80-W0902-1 Rev C



Section 7-14


Hybrid 1X / EV-DO PRL – Section Review

1. What revision of IS-683 supports EV-DO systems?

2. How does IS-683C support EV-DO systems?

3. What comprises the Subnet ID and how is it used in the PRL?

4. What is the purpose of the Subnet ID length?

5. What does a Subnet ID length of 0 indicate?

6. Can a 1X system be associated with more than one EV-DO system? Vice versa?

Review

1. IS-683C includes support for EV-DO systems in the PRL.

2. IS-683C supports EV-DO systems by providing:

New extended system record that supports EV-DO systems

New generic acquisition record that supports EV-DO systems

New association fields to link 1X and EV-DO systems

3. The Subnet ID is composed of a 104-bit Subnet ID Part and a 24-bit Sector ID Part. It is used as the system ID in EV-DO system records. The Subnet ID Part and Sector ID Part are similar to the SID and NID used with 1X systems.

4. The Subnet ID length indicates how many bits of the Subnet ID are significant. Only these significant bits are used for matching Sector ID values being broadcast.

5. A Subnet ID length of 0 is a wildcard that indicates that no bits of the Subnet ID are significant. Therefore, any Sector ID being broadcast will match. The danger in using such wildcard values is that non-roaming partner systems can be acquired, even though the user will not be able to receive service from the acquired system.

6. Yes, each association tag value identifies a set of one or more EV-DO systems. Any number of 1X systems may link to that set of EV-DO systems by using that association tag value.


PRL Technical Workshop 80-W0902-1 Rev CSection 8: Use of the Hybrid 1X / EV-DO PRL



Section 8-1


Section 8:Use of the Hybrid 1X / EV-DO PRL

Use of the Hybrid

1X / EV-DO PRL8SECTION

Notes





Section 8-2



Explain 1xEV-DO system selection.Define system scanning.Explain hybrid system selection.Explain avoidance of unusable 1xEV-DO systems.Explain system loss in hybrid mode.

Notes





Section 8-3


Hybrid System Determination

Hybrid System DeterminationA 1xEV-DO device uses the hybrid mode Hybrid System Determination process to attempt to:

Identify the best 1X/IS-95 and 1xEV-DO systems based on the device and the conditions at the locationAcquire the best systems as quickly as possible

For any given environment the charter of any Hybrid System Determination is to: Try to acquire a specific 1X/IS-95 system, Stay on the current serving 1X/IS-95 system, orEnter 1X/IS-95 power save mode

ANDTry to acquire a specific 1xEV-DO system, Stay on the current serving 1xEV-DO system, orEnter 1xEV-DO power save mode.

Hybrid System Determination draws on information from various sources, namely:Static information such as device settings and PRL.Dynamic information such as the broadcast SID/NID or subnet, the RF conditions and protocols in use.User activity.

This description is a general guideline. Questions on actual implementation should be directed to device manufacturers. Hybrid mode system determination has two distinct phases: CDMA System Determination followed by 1xEV-DO System Determination. Each phase has two stages. System scanning to find a system, and then, applying system selection criteria to the system that hasbeen found. 1X/IS-95 system acquisition always occurs first. In some implementations, 1xEV-DO may not be acquired unless a 1X/IS-95 system is found first; while, in others acquisition procedures may allow 1xEV-DO acquisition after the 1X/IS-95 acquisition fails. In the situation where a 1X/IS-95 system is acquired, the 1xEV-DO search would be limited to the associated 1xEV- DO systems in PRL. Although in reality the two stages of each phase are very closely coupled, for the purposes of explanation, each will be described separately.





Section 8-4


Device Settings & Modes of Operation

• Preference mode• Hybrid preference mode• Single system (non hybrid) mode

– 1xEV-DO-only mode. – CDMA 1X-only mode.

• Dual system (hybrid) mode

PRL can contain system types Can Operate on Preference Mode

1x/IS-95 1xEV-DO Analog 1x/IS-95 1xEV-DO Analog

Can be in Dual System (Hybrid)

Mode

Digital only *

Analog only * *

Automatic (determine mode

based on PRL)

1X only *

1xEV-DO only * *

1X and analog only * * ignored if present

Device Settings & Modes of OperationThere are settings on a 1xEV-DO device that will affect system selection behavior. Additional permutations are introduced by having a two modes. A 1xEV-DO device can be configured for single system or dual system operation. In single system configurations it can operate on a 1X/IS-95 system or a 1xEV-DO system. In dual system operation mode (often referred to as hybrid mode) it can operate on both 1X/IS-95 and 1xEV-DO systems concurrently.Preference Mode – controls the types of systems upon which a device can operate. With 1xEV-DO terminals, there are more variables, since in effect 1xEV-DO is a new mode and there are more combinations.Hybrid Preference Mode – governs whether the 1xEV-DO device is permitted to operate in hybrid mode. There are only two preference mode settings when hybrid preference mode setting is considered – Digital Only and Automatic.Dual System (Hybrid) Mode – a hybrid access device supports services on 1X/IS-95 and 1xEV-DO with handoff of a packet data session between 1X/95 and 1xEV-DO. The hybrid device can register and receive pages on 1X/95 and 1xEV-DO. A device can be configured to operate in dual system (hybrid) mode in one of two ways. (1) Set preference mode to Digital Only, set the hybrid preference mode to “Enabled” and a PRL describing 1X/IS-95 and 1xEV-DO systems appropriately. (2) Set the preference mode to automatic, set the hybrid preference mode to “Enabled,” and load a PRL on the device that describes both 1X/IS-95 and 1xEV-DO systems. Typically, when preference mode is set to anything other than “automatic” or “digital only,” the hybrid preference setting may be ignored. When preference mode is set to “automatic” or “digital only,” and the hybrid preference setting is set to off in an attempt to configure the DO device to acquire the 1X/IS-95 or 1xEV-DO systems, but not both. Typically, this mode of operation is not supported. Single System (Non Hybrid) Mode – in this setting, a 1xEV-DO device is capable of functioning on either a 1X/IS-95 or a 1xEV-DO system—it cannot operate on both systems simultaneously.

1xEV-DO-only mode CDMA 1X-only mode





Section 8-5


1xEV-DO Scanning

• Recent Channel or Most Recently Used List

• Forming the 1xEV-DO Scan List:– 1xEV-DO channels from the most recently used table, and

– 1xEV-DO channels from the acquisition table in the PRL.

• Types of 1xEV-DO Scan Lists: – Collocated Scan List

– 1xEV-DO system Lost Scan List

– All Collocated 1xEV-DO Scan List

1xEV-Do Scanning

Scanning concepts are similar for 1xEV-DO with some subtle changes.

Recent Channel or Most Recently Used List

Devices maintain a Most Recently Used (MRU) table. Typically, in a 1xEV-DO device, there is still just one MRU table except now its space is allocated between remembering the 1X/IS-95 systems and the 1xEV-DO systems that have provided service. The MRU table does not record any association information. The number of total entries in a hybrid mobile device’s MRU list is implementation dependent but a typical number may be 12. The allocation split between 1X/IS-95 and 1xEV-DO systems is also implementation dependent but a typical split may be 11/12 entries for 1X/IS-95 and 1/12 entries for 1xEV-DO.

Types of 1xEV-DO Scan List

Just like for 1X/IS-95 operation, the 1xEV-DO device builds a scan list dynamically. The building of scan lists, their names and uses, is not standardized and is left to the implementation. Therefore, how the scan list is constructed is a function of the particular vendor’s implementation of system determination. In general, scan lists are formed from:

1xEV-DO channels from the most recently used table 1xEV-DO channels from the acquisition table in the PRL




Collocated Scan List

This scan list is constructed when:

The device has successfully acquired 1X/IS-95 service, and

The acquired 1X/IS-95 system has been associated with one or more 1xEV-DO systems.

1xEV-DO System Lost Scan List

This scan list would be constructed when 1xEV-DO service is lost. The list contains an ordered list of 1xEV-DO channels comprising the channel of the 1xEV-DO system that has just been lost, channels of the 1xEV-DO MRU table, and all 1xEV-DO channels described in the acquisition records of any 1xEV-DO systems with the same association tag (only within the same GEO) as the serving 1X/IS-95 system.

A common 1xEV-DO reacquisition schedule is one which places the lost system only at the head of the scan list and performs no further interspersal. Duplicates are removed as are any channels that are outside of the permitted band classes of the band preference setting.

All Collocated 1xEV-DO Scan List

This scan list is constructed, in hybrid mode, when attempts to acquire 1X/IS-95 service fails. Under such conditions there is no association information available to guide the 1xEV-DO search. The list contains any 1xEV-DO channels in the MRU table followed by all 1xEV-DO channels referenced by the 1xEV-DO system records that have membership of any association set (i.e., have an association tag defined). Typically, the order of the 1xEV-DO channels in the scan list is derived from the order in which the referencing system records appear in the system table (from top to bottom) .





Section 8-7


Hybrid System Selection

Power up

1x acquisition 1x IDLE 1xEV-DOacquisition

1x + 1xEV-DOIDLE

Power up

1x acquisition 1x IDLE1x IDLE 1xEV-DOacquisition

1xEV-DOacquisition

1x + 1xEV-DOIDLE

1x + 1xEV-DOIDLE

Hybrid System Selection

The hybrid device attempts to performs 1X/IS-95 system determination first. Once the best available 1X/IS-95 system has been selected, an attempt is made to acquire the best available 1xEV-DO system, as is depicted above. Generally, the hybrid device will attempt to acquire an 1xEV-DO system only once a 1X/IS-95 system has been acquired and then only one that is in the same association set scope as the serving 1X/IS-95 system in the PRL.





Section 8-8


Hybrid System Selection (continued)

Initial System Selection

This slide shows a generalized example of the components of a hybrid system. On initialization, the hybrid device searches for an available 1X/IS-95 system and attempts to acquire it first (as described by section 5.3.2). During this time the radio interface is dedicated to 1X/IS-95 system acquisition. In 1X/IS-95 initial system selection, the state of the environment was simply described as the presence or nonpresence of a usable system. In hybrid operation, during initialization, the combination of the states of both the 1X/IS-95 and 1xEV-DO environments now yield one of four possible environment conditions that may exist:

Both 1X/IS-95 and 1xEV-DO systems are available.

1X/IS-95 systems are available and no 1xEV-DO systems are available.

No 1X/IS-95 systems are available and 1xEV-DO systems are available.

Neither 1X/IS-95 nor 1xEV-DO systems are available.

Both 1X/IS-95 and 1xEV-DO Systems Available

Where both systems are available the hybrid device acquires 1X/IS-95 first. Once idle on 1X/IS-95, it attempts to acquire a 1xEV-DO system in the association set using channels of the Collocated Scan List (see section scan list, starting from the top). If a 1xEV-DO system is acquired that is listed in the PRL’s system table and is the most desirable system in the association set, then service is provided on that system and no further 1xEV-DO scanning is performed—until the system is lost. If the device acquires a 1xEV-DO system that is listed in the PRL (system table) that it is not the most desirable system in the association tag scope of its geographic region, the device may search using the better 1xEV-DO service scan list. Once both systems are acquired the hybrid device enters idle mode operation on both the 1X/IS-95 system and the 1xEV-DO system.




Only 1xEV-DO Systems Available (No 1X/IS-95)

If there is no 1X/IS-95 system available, as per the definition in the PRL, the hybrid device may attempt to search for a 1xEV-DO system, depending in the implementation. In some implementations, the hybrid device dedicates its radio resources to acquire 1X/IS-95 and does not attempt any 1xEV-DO acquisition until a 1X/IS-95 system is acquired. In later implementations, a hybrid device can operate on 1xEV-DO in the absence of a 1X/IS-95 system. The 1X/IS-95 part of the device remains in 1X/IS-95 power save mode while the 1xEV-DO system is operational. Where supported, 1xEV-DO acquisition, in the absence of 1X/IS-95, is performed using the All Collocated 1xEV-DO Scan List.

Only 1X/IS-95 Systems Available (No 1xEV-DO)

If, once having acquired 1X/IS-95, 1xEV-DO acquisition using the Collocated Scan List fails to acquire any 1xEV-DO system, then the 1xEV-DO part of the device enters 1xEV-DO power save mode. Repeated attempts to acquire a 1xEV-DO system are typically performed at increasing intervals in order to optimize power consumption. An example of such a telescoping schedule may be for 2, 4, 10, 30, and 60 seconds.





Section 8-10


EV-DO System Selection

• If not the most preferred system – reselection occurs• A more preferred IS-2000 system. • If service is lost – reselection occurs

Dual Mode:• If new 1X/95 system is not associated with the current EV-DO system

– Attempts to acquire EV-DO associated with the new 1X/95 system.

System reselection

• Acquire the best available IS-2000 system per PRL• Upon successful acquisition of an IS-2000 system, device attempts to acquire the best available IS-856 system.

Dual Mode:• Only attempts to acquire an IS-856 system that is associated with the current IS-2000 system

Initial system

selection

Hybrid System Reselection

Since the hybrid device introduces two modes of operation there are also two modes of reselection:

1X/IS-95 System Reselection

1xEV-DO System Reselection

In each case, if the preferred roaming list indicates that the current serving system is not the most preferred system available in the priority scope (GEO for 1X/IS-95 and Association Tag set for 1xEV-DO), then the device may periodically attempt to acquire a more preferred system. Again, having two distinct modes means that there are more situations to consider.

Reselection on a Less Preferred 1X/IS-95 System

If service is lost, on either the 1X/IS-95 system or the 1xEV-DO system, the access terminal will either attempt to re-acquire the lost system or attempt to acquire another system, in accordance with the preferred roaming list. The action taken by the access terminal depends on the specific reason for the loss of service on the current system.

Whenever the device acquires a new 1X/IS-95 system, and the new 1X/IS-95 system is not associated in the PRL with the current serving 1xEV-DO system, the access terminal will try to acquire a 1xEV-DO system that is associated with the new 1X/IS-95 system.





Section 8-11


Avoidance of Unusable 1xEV-DO Systems

A device can declare a 1xEV-DO system to be unusable for a number of reasons, including the following:

• Protocol mismatch • 1xEV-DO redirection • Access denied • Session abort • Connection deny – general/network busy• HDR connection deny – authentication failure• Maximum Access probes

Avoidance of Unusable SystemsA device may encounter a 1xEV-DO system upon which it cannot provide service. A device can declare a 1xEV-DO system to be unusable for a number of reasons, some of which are:

Protocol mismatch 1xEV-DO redirection Access denied Session abort Connection deny—general/network busyHDR connection deny—authentication failureMaximum Access probes

Most implementations will avoid unusable 1xEV-DO systems. The actual period is implementation dependent. The condition causing the avoidance varies; avoidance times can range from 30 seconds to 10 minutes. Avoiding a 1xEV-DO system does not imply that a system is re-acquired after avoidance timer expires; it just means that it is eligible to be scanned again. During the avoidance time the channel is omitted from the 1xEV-DO scanning process. When the avoidance timer expires, the channel reenters the next scanning schedule. Max-Access Probe Exit ScanWhen an access attempt fails with maximum number of permitted access probes[1], the mobile device would normally use a maximum access probe exit scan list for reacquisition. This list is similar to a power up scan but lacks the channel on which the access attempt failed.[1] Access Probe is a term used to collectively mean a system access message, sent on the access channel, and the specific power level with which it is sent. If the mobile device does not get a response, it sends subsequent access probes (same message at increased power levels). Often described as raising its voice until it is heard. There is a predefined maximum number of probes a device can send and a maximum power it can use.





Section 8-12


System Loss

Device State Service Lost on Resultant System Determination action

1x/IS-95 1xEV-DO 1x/IS-95 1xEV-DO 1x/IS-95 1xEV-DO

1x/IS-95 system lost reselection. 1xEV-DO acquisition may also occur Idle

1xEV-DO system lost reselection

No action Session is handed down to 1x & 1xEV-

DO acq when idle on 1x

Idle

Connected No action until 1xEV-DO idle. Session continues in connected state.

1x/IS-95 system lost reselection. 1xEV-DO acquisition may also occur Connected Idle

No action No resel on DO until 1xEV-DO system lost reselection when idel on 1x/IS-95

System Lost

With the hybrid device system, lost requires further qualification to determine what should happen. There are three basic pieces of information that are required to understand what the next steps should be:

which system is lostthe relevant system loss scan lista relevant system loss service scan

When a mobile device has declared that it has lost a system[1] it invokes its system lost reselection policy. The “schedule” of attempts to reacquire the system that has just been lost is set and driven by the construction of the system lost scan list. As in better service reselection, if a system is acquired and it is less-preferred, then better service reselection will be performed. It is worth noting that often the system determination will search through the GEO first.

1X/IS-95 Idle and 1xEV-DO System Lost while Idle

If a 1xEV-DO system is not available, the AT acquires a 1X system and then, after repeated attempts to acquire a co-located 1xEV-DO system, enters power save mode on the 1xEV-DO system. In idle state, the device monitors both CDMA2000 1X and 1xEV-DO systems. The wakeup slot for 1X should not overlap with the preferred control channel cycle for 1xEV-DO.

1xEV-DO connected and 1X/IS-95 Lost

In some implementations there may be no attempt to acquire 1X/IS-95 service while 1xEV-DO is in the connected state. Other implementations may permit 1X/IS-95 acquisition but enforce some form of throttling scheme so as not to starve the connected 1xEV-DO session of radio resources. A common throttling scheme is to return to the 1xEV-DO session for a telescoping period of time while 1X/IS-95 system is unavailable and 1xEV-DO is connected.

1xEV-DO System Lost while in Connected State

If the hybrid device is in a 1xEV-DO connected state and moves to a location where there is no 1xEV-DO coverage, data session handoff to 1X/IS-95 system takes place.

[1] The signal level that a mobile device declares that it loses a system is implementation dependent. A CDMA system is normally unusable an at Ec/Io of -16 dB or lower.





Section 8-13


Use of the Hybrid 1X / EV-DO PRL –Section Review

1. When is the Collocated Scan List built and used?

2. What EV-DO channels are included in a Collocated Scan List?

3. What is the scope of an association tag?

4. What happens if the device is unable to successfully acquire an IS-95/1X system?

5. What will be the device’s behavior when a most preferred IS-95/1X system but less preferred associated EV-DO system is acquired?

6. If an EV-DO system has already been acquired and the device selects a new IS-95/1X system with a different association tag, is there any change to the EV-DO system?

7. What typically occurs when an EV-DO system is deemed unusable on a particular channel?

Review

1. The Collocated Scan List is built and used after an IS-95/1X system with an association tag has been successfully acquired (i.e., device is in idle mode on the IS-95/1X system).

2. The Collocated Scan List contain all EV-DO channels referenced by EV-DO system records with the same association tag as the acquired IS-95/1X system. It also includes EV-DO channels from the MRU table.

3. Association tags only have meaning within a GEO (i.e., IS-95/1X systems in a GEO can only be associated with HRPD systems in the same GEO).

4. Most hybrid devices, upon failing to acquire an IS-95/1X system, will build an ‘All Collocated 1xEV-DO Scan List’ and use it to attempt to acquire an EV-DO system. Because there is no IS-95/1X system for association, this scan list will include all EV-DO channels referenced by EV-DO system records with any association tag (as well as EV-DO channels from the MRU table).

5. The device will periodically attempt to acquire a more preferred EV-DO system from the same association tag set. This does not effect the acquired IS-95/1X system.

6. Yes, if a new IS-95/1X system with a different association tag is acquired, the device will attempt to acquire an EV-DO system associated with the new IS-95/1X system.

7. When an EV-DO system is deemed unusable, the device typically starts an avoidance timer and the unusable channel is omitted from scan lists during this avoidance period.




Comments/Notes


PRL Technical Workshop 80-W0902-1 Rev C

9-1

Section 9: Writing a Hybrid 1X / EV-DO PRL




Section 9-1

Section 9:Writing a Hybrid 1X / EV-DO PRL

Writing a Hybrid

1X / EV-DO PRL9SECTION

Notes

9-1For Reliance Communications internal purposes only. Not to be shared externally.


9-2





Section 9-2Section Learning Objectives

List the Hybrid PRL design considerations.Explain how to write an EV-DO Acquisition Record.Explain how to write an EV-DO System Record.

Notes



9-3





Section 9-3

Things to Consider When Writing an EV-DO PRL

Coverage considerations• What is the coverage of the deployed system going to be?

– EV-DO coverage is always a subset of IS-95(A,B)/1X.• IS-95(A,B)/1X coverage is essential for Hybrid mode.

Hybrid mode• EV-DO system is always associated with IS-95(A,B)/1X system.• Multiple EV-DO systems can be associated with a single IS-95(A,B)

/1X system.• A single EV-DO system can be associated with multiple IS-95(A,B)

/1X systems.• A 1X or an EV-DO system can only be in one association.

EV-DO reselection may not work the same way as 1X.• Reselection period

Notes



9-4





Section 9-41xEV-DO PRL Design Considerations

• Subnet Access restrictions

• Geographical areas

• Associating EV-DO with 1X/95 systems

• Is EV-DO service provided while roaming in IS-95(A,B) /1X network of roaming partner?

• Is roaming into EV-DO network of roaming partner permitted?

Subnet Access RestrictionsCan restrict users to particular subnet areas by use of the Subnet ID entry. A good idea is to consider if the subnet is to be a criterion for EV-DO system access. If not, then use wildcard Subnet ID /0 for all entries.

Geographical Areas

As before, the number of geographical regions is an important design consideration.For an EV-DO overlay, underlying existing geographical area design is a useful consideration. In this situation, it would be useful to identify which of these geographical regions have EV-DO service available.

Associating EV-DO with 1X/95 systemsWithin a given region, which 1X/95 systems (SID/NIDs or channels) have associated IS-856 systems?

– Multiple IS-856 systems, distinguished by channels or subnets, can be associated.– Some IS-856 systems can be configured to be more preferred than the others.

It is important to understand whether roaming into the EV-DO network of a roaming partner is permitted. If EV-DO service is to be provided while roaming in an IS-95(A,B)/1X network of a roaming partner, those systems must be associated with the IS-95(A,B)/1X roaming network.

It is not permitted to associate an EV-DO system with any analog system.



9-5





Section 9-5Varying EV-DO Coverage

• Ubiquitous 1X coverage

• Varying EV-DO partner footprints

• Which partner is preferred?

• Which associations are to be defined?

19:2:3:4:5:6:7:8315001311

PRI

21

1X Pri

9:2:3:4:5:6:7:8240019:2:3:4:5:6:7:819001

EV-DO SubnetAssoc.1X SID

9001

4001

15001

9:2:3:4:5:6:7:8

4:2:3:4:5:6:7:8

15:2:3:4:5:6:7:8

39:2:3:4:5:6:7:815001321

PRI

21

1X Pri

9:2:3:4:5:6:7:840019:2:3:4:5:6:7:8

19001

EV-DO SubnetAssoc.1X SID

Notes



9-6





Section 9-6How to Write an EV-DO PRL

• First, set the PRL format to IS-683C.

• Then, to create an EV-DO acquisition record:

– Set the Acq Type field to HDR Channels.

– Select the band class of the first channel.

– Enter the channel number of first channel.

– Enter additional band class/channel number pairs, as desired.

Notes



9-7





Section 9-7How to Write an EV-DO PRL (continued)

To create an EV-DO system record:

• Set System Type field to IS-856 System.

• Enter fields as in IS-683A:– Neg/Pref– Geography – Priority– Acq Index – Roam Indicator

• Leave SID and NID fields empty (editor-dependent).

• Enter Subnet ID in “Subnet ID” field.

“Subnet ID” field

IPv6 address text string representation of x:x:x:x:x:x:x:x/lenx’s are the hexadecimal values of the eight 16-bit pieces of the 128-bit address.len is the length of the subnet ID, which must be in the range of 0-127.

Only the value of the first len bits is important; therefore, only such bits are saved with the PRL file. Any bits that are outside len may be set to 0. For example: 0:0:0:0:0:0:0111:0/104 Is equalto: 0:0:0:0:0:0:0100:0/104

To specify a wildcard subnet ID:Set len to 0. For example: 0:0:0:0:0:0:0:0/0 The shorthand notation /0 can also be used to specify the wildcard subnet ID. It is not necessary to write the leading zeros in an individual field, but there must be at least one numeral in every field. For example: 0000:0000:0000:0000:0000:0000:0100:0000/104 can also be entered as: 0:0:0:0:0:0:100:0/104

Only the value of the first len bits is important; therefore, only such bits are saved with the PRL file. Any bits that are outside len may be set to 0. For example: 0:0:0:0:0:0:0111:0/104 is equal to 0:0:0:0:0:0:0100:0/104



9-8





Section 9-8Association of IS-856 Systems

• “Association Tag” links IS-856 system with IS-2000/IS-95 systems:– Association tag is an 8-bit field with values between 0 and 255.– Only systems in the same GEO can be associated.– set the Assn Incl field to Yes, and enter a 0-255 value in the Assn Tag field. – Set same association tag value for the associated IS-2000 system – Set the PN Assn and Data Assn fields to No (Not used).

• “PN Association” indicates that the IS-2000 and IS-856 systems have the same PN offset.

• “Data Association” indicates that the IS-2000 and IS-856 systems are using the same PDSN.

GEO

Association Tag1X (SID) systems

EV-DO systems

Association Part

The presence of an association is indicated by the field ASSOCIATION_INC. having a value of 1. There are three associations that comprise the association part of the system record.

The first, and most significant in use today, is the ASSOCIATION_TAG. This is an 8-bit number that names the “association set” to which this system record belongs. The set name has meaning only within the scope of a GEO. System records in the same GEO that have the same Association Tag are members of the same set. System records in different GEOs that have the same Association Tag are not members of the same set.

The other two associations, while present in the PRL, are not currently used by system selection but their description is included here for completeness:

PN association flag – identifies systems that have the same PN offset assignment (i.e., collocated). Data association flag – identifies systems that can reach the same set of PDSNs (i.e., associated).



9-9





Section 9-9

Writing a Hybrid 1X / EV-DO PRL –Section Review

1. Can an analog system be associated an EV-DO system?

2. What is the Acquisition Type of an EV-DO acquisition record?

3. What is the System Type of an EV-DO system record?

4. Subnet ID fields used to identify EV-DO systems are IPv6 addresses. (True or False)

5. How is a wildcard Subnet ID specified?

Section Review

1. No, analog systems cannot be associated with EV-DO systems. Only IS-95/1X systems may be associated with EV-DO systems.

2. “HDR Channels” acquisition type is used for EV-DO acquisition records.

3. “IS-856 System” system type is used for EV-DO system records.

4. False; while the Subnet ID is represented using the IPv6 address format, Subnet IDs are not actual IPv6 addresses.

5. A wildcard Subnet ID is specified by setting the Subnet ID length to 0 in an EV-DO system record.



9-10



Comments/Notes




Section 10: PRL Enhancements


Section 10-1


Section 10:PRL Enhancements

PRL Enhancements10SECTION

Notes






Section 10-2



Recognize the need for PRL enhancements.List CDG PRL enhancements for Roaming.Explain how to implement PRL enhancements.Discuss infrastructure and handset capability.Define operator activities.Describe PRL generation.Explain the impacts on handset configuration.

Notes






Section 10-3


The Need for PRL Enhancements

• A SID normally covers the area of a city or large town.

• A NID is a subset of a SID (different rating areas, toll areas, private networks, MSC boundaries, etc.).

• National wireless carriers’ networks may cover a large number of SIDs (tens or hundreds).

• When international roaming is required, PRLs become significantly larger due to the inclusion of the roaming partners’ SIDs:– More memory required in the handset of R-UIM

– Larger PRL download times (OTA)

– Difficult to keep updates in handsets

The Problem of Tracking SIDs

A broadcast SID normally covers the area of a city or large town, or a state. The Network ID can further divide a SID area as necessary. A national wireless network can comprise tens or hundreds of SIDS. When international roaming is required, a PRL becomes significantly larger because of the need to include the roaming partners’ SIDs. This means more memory is required in the handset or R-UIM and can also mean longer over-the-air download times for a PRL.

Changes in the use of SIDs in the roaming partner’s networks’ must be tracked and can result in a modification to the PRL that must be redistributed to all affected handsets. If memory is an issue, an operator may have to choose which markets in a roaming partner’s network are most important to them and include only those that can result in reduced coverage.

In addition, if broadcast SIDs change as a result of network expansion or SID consolidation, a roaming partner must modify their PRL if they want to take advantage of the changed coverage.

Being able to describe the roaming partner’s network at the network level as opposed to the SID level would remove this issue from PRL management.






Section 10-4


CDG Resolution for PRL Enhancements

Mobile Country Codes and Mobile Network Codes (Operators)• Operators obtain and use MCCs and MNCs (IMSI_11_12) for their CDMA network.

Use existing broadcast mechanisms for this information (Infrastructure)• Ensures valid information is being broadcast in the Extended System Parameters

message.– MCC is mandatory.– IMSI_11_12 is mandatory.

Enhanced PRL system table entry (PRL)• Allows the description of a system by:

– SID/NID– MCC/MNC (IMSI_11_12)

Enhanced system determination (Handset)• Uses the MCC/MNC (IMSI_11_12) scheme in system selection.

Backward compatibility (Existing Infrastructure & Handsets)• Presence of a MCC/MNC (IMSI_11_12) entry in the PRL will not “break” the following:

– Existing handset system determination– Existing PRL management mechanisms

CDG Resolution for PRL Enhancements

CDG Reference Document #86 describes PRL Enhancement in terms of how CDMA networks can, for the purposes of system selection, identify themselves and be recognized at the “network level.” Through appropriate use of current broadcast information in the Extended System Parameters, a network can identify itself in terms of its Mobile Country Code (MCC) and Mobile Network Code (MNC) or “IMSI_11_12” as it is referred to in the CDMA standards.

A specially encoded entry, known as an MCC/MNC system table record, in the existing form of the PRL allows the description of a network by its MCC and MNC (or IMSI_11_12) by use of a specially reserved SID and the NID to hold an encoded form of the MCC and MNC.

The System Determination function of the handset is now extended to allow system selection using a MCC/MNC (IMSI_11_12) scheme.

The PRL enhancements are fully backward compatible. A PRL containing a MCC/MNC system table record can be loaded into any handset whether or not it supports the enhanced system selection. Since the MCC/MNS system record has the same form of existing system records, the presence of a MCC/MNC (IMSI_11_12) entry in the PRL will not “break” any existing handset system determination or existing PRL management mechanisms.






Section 10-5


Identifying a System

Every CDMA system broadcasts in System Parameters messages.

• System Identification (SID)• Network Identification (NID)• Mobile Country Code (MCC)• IMSI_11_12 (akin to Mobile Network Code

– MNC)

Currently the CDMA granularity of roaming control is the SID/NID pair.

• One description of a particular market within the carrier’s network as chosen by the carrier.

• Provides good control for the carrier of how to describe the network.

Now the CDMA operator may describe their network both ways:

• Using the granularity of SID/NID for its own users and other roaming partners as needed.

• Using the MCC + IMSI_11_12granularity for roaming partner PRLs that do not require SID/NID information.

• Both can be used in combination.

SID & /NIDMCC & IMSI_11_12

SID/NIDMCC/IMSI_11_12

SID/NIDMCC/IMSI_11_12

Identifying a CDMA System at the Network Level

To understand how a CDMA network can identify itself at the network, let’s look again at CDMA network identification. We have already established that the CDMA system broadcasts its System Identification (SID) and Network Identification (NID). Every CDMA system broadcasts two other identification parameters in the Extended System Parameters message, namely the Mobile Country Code (MCC) and the IMSI_11_12 (also known as the Mobile Network Code – MNC).

Granularity of a Network Description

In GSM the description level of granularity, for the purposes of selecting a network, is the PLMN (Public Land Mobile Network) Identity. A PLMN ID is the MCC and the MNC. One description describes a complete carrier’s network, or part thereof where a carrier has more than one MNC,

In CDMA the currently used description level of granularity, for the purposes of selecting a network, is the SID/NID pair, which is one description of a particular market within the carriers network as chosen by the carrier. This provides very good control for the carrier of how to describe the network and hence select a network, particularly when there are multiple networks present. However, the cost of using only this level of detail in a multiple carrier home market is that roaming partners must also describe the network at this level of detail and hence they must know and track all their partners’ SID/NID definitions and incorporate them into their PRL.

However, the CDMA networks have the inherent ability to allow their operators to describe their network both ways, and both can be used simultaneously. System selection implementations always match at the finer level of granularity. Therefore, combining the MCC/MNC and SID/NID levels of granularity presents a host of options to the CDMA operator, for example:

Using the granularity of SID/NID for its own users and domestic roaming partners Using the MCC + MNC(IMSI_11_12) granularity so roaming partner PRLs do not have to contain all the SID/NID information






Section 10-6


PRL Enhancements – How They Work

PRL• Can describe a system by:

– SID/NID – MCC/MNC

• Full backward compatibility is supported.

System determination• Updated system selection software to use the enhanced

format.• Existing system selection will process enhanced format as

normal SID/NID entries.

Use of a valid MCC and IMSI_11_12• ITU issues MCCs • Each country administers allocation of Network codes in the

US the administrator is Telcordia (www.imsiadmin.org)• CDMA air interfaces currently support the broadcast of a 2-

digit MNC. (As in GSM)

Configuring network to use these values in its broadcasts:

• The network is currently broadcasting something – the manufacturer default if it has not be set by the operator.

• Configuration with the real MCC/MNC values is required for the enhancements to work.

System Parameters: {SID=8742, NID=65535}Extended System Parameters: {MCC=310, IMSI_11_12=10}

Handset View of the PRL Enhancements Network View of the PRL Enhancements

BSC

AbisBSC

CDMA/OTA

CSC

Carrier - System(SID, NID) or (MCC/MNC)

Selection Pref

Roaming Indicator

Acquisition Index

MCC/MCC=310,10 First ON 0MCC/MCC=310,42 Second ON 0

Permitted Systems

Geo: CountryXGeo: CountryX

System Table: Geo entries requires for CountryX

CDMAroamer

MSC

PRL Enhancements – How They Work

A PRL can describe a system by SID/NID or MCC/MNC, or both. The MCC and MNC are encoded into the existing SID and NID fields such that full backward compatibility is achieved.

Handset

An enhanced system determination is needed to use the MCC/MNC system record. This enhanced system determination has been available in all QUALCOMM MSM 6xxx series chipsets since April 2004. With this enhanced system determination, the device reads the MCC and MNC information from the Extended System Parameters Message and uses them to perform PRL matching when dealing with MCC/MNC system record.

If system determination is not updated, and the PRL has MCC/MNC type entries, they will appear as normal SID/NID entries. Since the two special SIDs used in the PRL encoding are never broadcast on any system, those entries will never trigger a match and thus have no effect on system selection.

Network

The CDMA 2000 (Revisions 0 and A) air interfaces currently require the broadcast of a 2-digit MNC. (IMSI_11_12) and a 3-digit MCC in the Extended Systems Parameters message. Since these are mandatory parameters of this message, each CDMA system must, and currently does, broadcast a value in these fields. These current values may be the manufacturer default if it has not be set by the operator, or, they may be the wildcard values for MCC and IMSI_11_12.

For the PRL enhancements to function, the network must be configured to broadcast the real values allocated to the operator.






Section 10-7


Use of Existing Standards

The resolution: • Does not modify any CDMA standard.

• Describes a uniform method for populating and using existing data elements currently in use.

• Does not impose any requirements on the use or not of full-IMSI in the core network (ANSI-41).

• Describes an encoding convention to describe a system by its MCCand IMSI_11_12 in the SID and NID space of a PRL entry:

– MCC10 bits+ IMSI_11_127 bits = 17 bits

– SID = 15 bits, NID = 16 bits

– Use of NID for MCC9 bits+ IMSI_11_127 bits

– Use of 2 special SIDs for MCC10 (values of 15904=0 and 15905=1)Used worldwideNot in use by any other operator

Standards Affected by PRL Enhancements

The resolution does not modify any CDMA standard. It describes a uniform method for populating and using existing data elements currently in use. It does not impose any requirements on the use (or not) of full-IMSI in the core network (ANSI-41).






Section 10-8


Implementing the CDG Resolution

US Operator

Foreign Operator4

InfrastructureConfiguration

PRL Management

CDG

Network DataAdmin

ii

2 3

1

TDS

Handset Supplier

MSProgramming

MSProgramming

b

c

d

Enhanced PRL Roaming

e

i

Infrastructure Supplier

a

iii

Network DataAdmin

MCC/MNCAdministrator

(USA: Telcordia)

MCC(s)ITU

Steps for Implementation of PRL Enhancements

Obtaining MNC

The first stage in implementing the PRL enhancements is to obtain the valid MCC and IMSI_11_12 for their network(s).

Infrastructure

Infrastructure changes include:Configuring infrastructure and verifying the broadcast of valid MCC and IMSI_11_12 valuesInforming roaming partners of MCC/IMSI_11_12 values in Technical Data Sheet (TDS) exchange

Mobile Devices

Changes for mobile devices include:Specifying the PRL Enhancement behavior in handset specificationsBuilding and distributing new PRLs with the more streamlined MCC/MNC entries






Section 10-9


CDG Coordination Roles

IFAST and Special SIDs• IFAST has approved the following allocation 15904-15905.

Mobile Network Code Convention• Coordinate a proposal to Telcordia on allocation guidelines for

CDMA operators’ Mobile Network Codes.

• Assist in other countries where an MNC usage convention may need to be adopted if required.

Notes






Section 10-10


PRL Enhancements –Impacts on Infrastructure

Infrastructure impacts:• IMSI aspects are supported on the

over-the-air aspects of the system only.

• MCC and IMSI_11_12 are sent in the Extended System Parameters message by the Base Station.

• Operators must be able to configure systems to broadcast their own MCC and IMSI_11_12.

– Most are broadcasting something other than wildcards.

– Many have manufacturer default values.

• No migration to full IMSI in the ANSI-41 Core Network is required.

1RESELECT_INCLUDED

3MAX_NUM_ALT_SO

8PACKET_ZONE_ID

6DROP_INTERCEPT

6ADD_INTERCEPT

6SOFT_SLOPE

8MIN_P_REV

8P_REV

1IMSI_T_SUPPORTED

3BCAST_INDEX

8 x TMSI_ZONE_LENTMSI_ZONE

4TMSI_ZONE_LEN

7IMSI_11_12

10MCC

2PREF_MSID_TYPE

1USE_TMSI

1DELETE_FOR_TMSI

6CONFIG_MSG_SEQ

PILOT_PN

Field

9

Length (bits)

PRL Enhancements – Impacts on Infrastructure

IMSI aspects are supported on the over-the-air aspects of the system only. MCC and IMSI_11_12 are sent in the Extended System Parameters Message by the Base Station. Operators must be able to configure systems to broadcast their own MCC and IMSI_11_12. Most are broadcasting something other than wildcards. Many have manufacturer default values. Others may be broadcasting standards-reserved wildcard values for MCC and IMSI_11_12.

No Migration to Full IMSI in the ANSI-41 Core Network is Required

The intended mode of broadcasting a carrier identification is by using the Mobile Country Code (MCC) and IMSI_11_12 parameters in the Extended System Parameters message. MCC is the Mobile Country Code assigned by ITU E.212. IMSI_11_12 is to be defined for each operator. Initially, the IMSI_11_12 can define up to 99 distinct carriers per MCC. The IMSI_11_12 could also be described as the two most significant digits of the MNC (Mobile Network Code) assuming a 3-digit MNC. These fields are already broadcast by CDMA operators. They are mandatory parameters in the Extended Systems Parameters message. However, not all carriers have had formal national assignments of IMSI_11_12 and some may not even be broadcasting valid information.

Effect on Access Channel Messaging

The Access Channel has a similar algorithm: The mobile is allowed to send only the 10-digit IMSI_S if the overhead and programmed MCC/IMSI_11_12 match. When these don’t match, the mobile is forced to send a full 15-digit IMSI. Again, having these values set correctly can imply savings on the air interface.

Effect on Traffic Channel Messaging

Whenever a mobile receives a page, the algorithm described by CDMA-2000 requires the mobile to perform a full 15-digit IMSI match to declare a “page match.” However, this 15-digit match is not required if the MCC and IMSI_11_12 broadcast by the network matches the MCCp and IMSI_11_12p programmed in the handset.

In other words, the service provider can page all the subscribers that are “Home” with a shortened version of the IMSI (only the IMSI_S, i.e., the least significant 10-digits), thereby saving considerable bandwidth on the Paging Channel.






Section 10-11


PRL Enhancements –Impacts on Handsets

Handset (mobile device) impacts:

• Existing handsets and existing System Selection implementations will not be “broken” by encountering an “enhanced PRL” entry.

• System selection must be upgraded to understand system described in terms of MCC, IMSI_11_12.– New format MCC, IMSI_11_12 records will be

ignored by existing system selection implementations.

• QCT 6xxx series chipsets have shipped with this functionality since April 2004.

• Complying with the new handset specs that operators will produce to require the PRL Enhancement.

PRL Enhancements – Impacts on Mobile DevicesMobile devices have storage locations for two types of IMSI: a MIN-based IMSI (IMSI_M) and true IMSI (IMSI_T). In IMSI_M, the MIN is fully contained within the MSIN. When both are present, the network overhead messages indicate which IMSI the mobile used. Once the mobile selects an IMSI, this becomes the operational IMSI, known as IMSI_O.

The mobile IMSI stored in non-volatile memory (or R-UIM) is 15 digits in length. Since most current deployed systems’ infrastructure do not support the true-IMSI on the core, many CDMA systems support only special 10-digit MINs known as International Roaming MINs (IRMs), which are globally unique. Once a mobile selects its operational IMSI, the IMSI has three separate states:

Programmed – denoted by the p subscript (e.g., Xp); refers to the value that has been programmed into the device by the operator.Received – denoted by the r subscript (Xr); refers to the value received over the air from the serving network.Stored – denoted by the s subscript(Xs); refers to the value that is selected by the mobile (between Xp and Xr) during the time it is served by this network

Operators have the choice of programming the MCCp and IMSI_11_12p of the subscriber’s IMSI or leaving them unused. CDMA has some other representations of the IMSI, including IMSI_S, IMSI_S1, and IMSI_S2.IMSI Use in the Pre-PRL Enhancement EnvironmentIt is recommended that the MCCp and IMSI_11_12p be programmed in the mobile. Specifically, both the MCCpand IMSI_11_12p programmed should match the broadcasted MCC and IMSI_11_12 from the Extended System Parameters Overhead message of the home network.System Selection System selection must be upgraded to understand a system described in terms of MCC, IMSI_11_12. Existing handsets and existing System Selection implementations will not be “broken” by encountering an “enhanced PRL”entry. Existing system selection implementations ignore new format MCC, IMSI_11_12 records. QCT chipsets have had this this functionality since April 2004. Operators’ handset specs are beginning to require the PRL Enhancement.






Section 10-12


System Parameters: {SID=8742, NID=65535}Extended System Parameters: {MCC=YYY, IMSI_11_12=xx}

[MCC, MNC]

PRL Enhancements –Aspects of Operator Implementation

Operators are responsible for:• Obtaining the valid MCC and IMSI_11_12

for their network(s).

• Configuring Infrastructure and verifying the broadcast of valid MCC and IMSI_11_12 values.

• Informing roaming partners of MCC/IMSI_11_12 values in Technical Data Sheet (TDS) exchange.

• Specifying the PRL Enhancement behavior in handset specifications.

• Building and distributing new PRLs with the more streamlined MCC/MNC entries.

TDS

Handset Specification

[MCC, IMSI_11_12]

New PRLs

Notes






Section 10-13


PRL Enhancement Resolution – Benefits

• Provides a more efficient means to describe a network in a PRL.– Knowledge of the use of SIDs and NIDs within a visited network becomes

optional.– National wireless carriers’ networks may cover a large number of SIDs

(tens or hundreds).

• Requires no changes to existing standards.– Existing messages/fields are populated with appropriate data.

• Does not require that full IMSI support be available in the corenetwork (ANSI-41) for its implementation.

• Allows for reduction in size of PRLs.• Allows international roaming partners to describe a greater

number of roaming networks in the same PRL size:– More efficient use of memory in the handset of R-UIM– Reduced PRL download times (OTA)– Easier to ensure foreign partners’ information is current

Notes






Section 10-14


PRL Enhancements – Section Review

1. What is an enhanced PRL system table entry?

2. How can using MCC/MNC reduce the size of a PRL?

3. Why might an operator want to use SID/NID to describe some systems in their PRL and MCC/MNC to describe others?

4. What must the Base Station broadcast to enable enhanced PRL functionality?

5. Do operators need to support IMSI in their core networks?

6. In addition to reducing the size of the PRL, what benefits does the use of MCC/MNC provide to operators with many international roaming partners?

Review

1. An enhanced PRL is one that supports identification of systems using SID/NID, MCC/MNC, or both.

2. A MCC/MNC pair uniquely describes an operator’s entire network in a country, requiring only one system table entry. However, the same network may use many SID/NID values, requiring many system table entries.

3. SID/NID provides a finer granularity of control for an operator to describe their own and, perhaps, their domestic roaming partner networks, while MCC/MNC provides a much more efficient method to describe international roaming partner networks. As such, it is common for enhanced PRLs to use both SID/NID and MCC/MNC identifiers.

4. To support enhanced PRL, Base Stations must broadcast correctly populated MCC and IMSI_11_12 (i.e., 2-digit MNC) values in the Extended System Parameters message (i.e., not manufacturer defaults or wildcard values).

5. No, this is a common misconception resulting from the fact that enhanced PRL uses MCC and IMSI_11_12. While these fields would also be used to support full IMSI in the core network, enhanced PRL only requires them to be correctly populated in the Extended System Parameters message sent over-the-air, regardless of whether IMSI is implemented.

6. Use of MCC/MNC instead of SID/NID to identify international roaming partner networks makes PRLs much easier to manage and ensures that roaming partner information is current.


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