C22-20080825-xxx

cdma2000 1x Signaling Enhancements for Femto AP Support

Contact:

Qualcomm

Peerapol Tinnakornsrisuphap (peerapol@qualcomm.com)

Ravi Patwardhan (rpatward@qualcomm.com)

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Airvana

Doug Knisely (dknisely@airvana.com)

Recommendation: Discuss and adopt

2

Introduction

• In order to more efficiently support Femto AP operations for cdma2000 1x and HRPD systems, we propose the following enhancements

– Allowing macro BS/AN to advertise the band/channels/PN offsets of femto APs deployed in the geographical region

• This allows the MS/AT to efficiently search for femto APs as part of system selection process during idle

• During connected state, MS/AT is also aware of which pilot belonging to a femto AP and may acquire more information about the femto AP if desired

– Allowing a femto AP to advertise a unique identifier and other information about the femto AP that assist system selection and handoff

– Allowing the MS/AT to report information that disambiguate the target femto AP during hand-in from macro BS/AN to femto AP

3

Proposed Messages

• Access Point ID Message (APIDM)– Similar to that proposed in [1]

– To support idle HO, active HO and Femto AP discovery

• Access Point Text ID Message (APTIDM)– To support manual scan and manual search of Femto AP

• Access Point Pilot Information Message (APPIM) – To support Femto AP discovery

• Handoff Supplementary Information Solicit/Notification (HSIS/HSIN)– The solicit message is to request information to disambiguate handoff

– The notification message is to give information to support active handoff from macro to Femto AP

* Note that this contribution focuses on 1x messages but similar concept can be applied to HRPD

4

Proposed Messages

• Access Point ID Message (APIDM)– Similar to that proposed in [1]

– To support idle HO, active HO and Femto AP discovery

• Access Point Text ID Message (APTIDM)– To support manual scan and manual search of Femto AP

• Access Point Pilot Information Message (APPIM) – To support Femto AP discovery

• Handoff Supplementary Information Solicit/Notification (HSIS/HSIN)– The solicit message is to request information to disambiguate handoff

– The notification message is to give information to support active handoff from macro to Femto AP

* Note that this contribution focuses on 1x messages but similar concept can be applied to HRPD

5

Access Point ID Message (APIDM)

• APIDM consists of:

– Association Type (3 bits)

– SID (15 bits)

– NID (16 bits)

– AP_ID_LEN and AP_ID

– AP_ID Mask (8 bits)

– MSC_ID (24 bits)

– CELL_ID (16 bits)

– HRPD Band Class and Channel (Optional)

– Location Information (Optional)• LAT (22 bits)• LONG (23 bits)• ALT (14 bits)• Horizontal and Vertical Uncertainty (5 bits each)

6

AP Identifier (AP_ID) and AP_ID Mask

• The AP_ID plus the SID/NID would define a globally unique identifier for access point

– AP_ID aids an MS for efficient system selection [2]• Simplify white/black list management

– The unique address can immediately indicate to the MS whether it is authorized to access an access point (to avoid needless registration and rejection)

– AP_ID length is configurable

• AP_ID Mask indicates the common MSBs of the AP_ID that belong to a pool

– E.g., for efficient identification of multiple APs belonging to a common enterprise

7

MSC_ID and CELL_ID

• These two fields are proposed to support active call hand-in

– MS would read the APIDM for the MSC_ID, CELL_ID of a target AP during an active call HO

• MS knows that the target PN belongs to an AP based on AP Pilot Information message

– MS would convey the MSC_ID and CELL_ID to its source sector to prepare the network and target AP for HO in Handoff Supplementary Information Notification message

• See next slide for example

8

Active Call Hand-in Ambiguity• Under the same macro BS, it is

likely that the same PN will be assigned to many Femto APs

• Macro BS needs to be able to resolve target MSC_ID and CELL_ID for the PN that has ambiguity

• Femto AP is configured with unique MSC_ID and CELL_ID. This information is advertised in the Femto ID message. The MS includes this info with the PSMM. The remaining standard handoff process will route the call to the MFIF (based on MSC_ID) and correct femto AP (based on CELL_ID) with no modification to A1 and IS-41 interfaces

Macro BSPN = a

Femto AP1PN = b

Femto AP2PN = b

MSC

MFIF

2. PSMM+ HSINM (<MSC_ID, CELL_ID>)

3. A1-Handoff Request<MSC_ID, CELL_ID>

4. IS-41<CELL_ID>

1. APIDM (MSC_ID, CELL_ID)

5. MFIF contactsFemto AP2 for handoff

9

Association Type

• There are three possible values for associations between MS and BS

– ‘000’ – Open association – the MS receives full service from the AP

– ‘001’ – Signaling-only association – the MS may register and receive page on the AP. However, when it requires connected state service, it needs to be redirected or connect to other BS

– ‘010’ – Restricted association – the MS, if unauthorized by the AP, rejects any request from the MS

– ‘000’-’111’ - Reserved

10

SID/NID, HRPD Info and Location Information

• We propose the transmission of SID, NID and location information in the AP ID message

• AP ID message is broadcasted by AP where these information can be used in conjunction with enhanced system selection [2] for the MS to make a decision whether to access the AP or not

• HRPD Information can help advertise HRPD channel associated with this femto AP so the MS/AT can find it in case of 1x/HRPD femto

11

Proposed Messages

• Access Point ID Message (APIDM)– Similar to that proposed in [1]

– To support idle HO, active HO and Femto AP discovery

• Access Point Text ID Message (APTIDM)– To support manual scan and manual search of Femto AP

• Access Point Pilot Information Message (APPIM) – To support Femto AP discovery

• Handoff Supplementary Information Solicit/Notification (HSIS/HSIN)– The solicit message is to request information to disambiguate handoff

– The notification message is to give information to support active handoff from macro to Femto AP

* Note that this contribution focuses on 1x messages but similar concept can be applied to HRPD

12

Access Point Text ID message

• The message contains variable length text string similar to the SSID in Wireless LAN

• Should be sufficient given the current screen constraint and usage model of WiFi identifiers

• The text string is used for assisting manual scan and manual white/blacklist

• International encoding is supported

• MS will not try to scan for this message while in active call

13

Proposed Messages

• Access Point ID Message (APIDM)– Similar to that proposed in [1]

– To support idle HO, active HO and Femto AP discovery

• Access Point Text ID Message (APTIDM)– To support manual scan and manual search of Femto AP

• Access Point Pilot Information Message (APPIM) – To support Femto AP discovery

• Handoff Supplementary Information Solicit/Notification (HSIS/HSIN)– The solicit message is to request information to disambiguate handoff

– The notification message is to give information to support active handoff from macro to Femto AP

* Note that this contribution focuses on 1x messages but similar concept can be applied to HRPD

14

Access Point Pilot Information Message (APPIM)

• APPIM consists of information that MS identifies which 1x pilot in the vicinity belongs to Femto AP

• Each record consists of <PN, BAND, FREQ> that are provisioned for APs in the area of coverage

• APPIM is advertised by macro BS and may also be advertisedby AP

• Efficient encoding of information is used to optimize these scenarios

– A few non-contiguous PNs are assigned to femto APs

– A range of contiguous PNs (spaced by PILOT_INC) is assigned to femto APs

– Same PNs are being assigned in different Band/Frequency

15

Usage of APPIM Message

• MS can scan for APs with this information – Each operator can statically configure APPIM to broadcast this

femto scan / deployment info within each region / cell– MS can use the information to decide whether it needs to decode

APIDM when it tries to idle/active handoff to that PN– MS would not need to be pre-provisioned with such scan

information especially when in roaming conditions– The MS retains the APPIM info once it acquires the information

and can use the stored information to scan for femto APs when no macro coverage is available

• APPIM can also be used to aid in Manual Scans of Femto APs

16

Proposed Messages

• Access Point ID Message (APIDM)– Similar to that proposed in [1]

– To support idle HO, active HO and Femto AP discovery

• Access Point Text ID Message (APTIDM)– To support manual scan and manual search of Femto AP

• Access Point Pilot Information Message (APPIM) – To support Femto AP discovery

• Handoff Supplementary Information Solicit/Notification (HSIS/HSIN)– The solicit message is to request information to disambiguate handoff

– The notification message is to give information to support active handoff from macro to Femto AP

* Note that this contribution focuses on 1x messages but similar concept can be applied to HRPD

17

Handoff Supplementary Information Notification / Solicit

• The notification message includes mapping between PN and <CELL_ID, MSC_ID> of APs that the MS considers to handoff to

– Purpose is to assist hand-in from macro to AP

– This message is sent along with PSMM

• The BS may request the information using the Handoff Supplementary Information Solicit message

18

Reference

[1] Airvana, “Signaling Enhancements for cdma2000 Air Interfaces to Enhance Operation with Femto Networks with Future Mobile Devices,” C20-20080331-017

[2] Airvana, ALU, IPComm, QC, Via, Femto related provisioning Enhancements for Enhanced System Selection (ESS) for Femto Cells – Update,” C14-20080331-009r1