02 rn20022en20gla0 (e)gprs signalling

8/13/2019 02 Rn20022en20gla0 (e)Gprs Signalling

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RN20022EN20GLA0

(E)GPRS Signaling

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1 © Nokia Siemens Networks RN20022EN20GLA0

EGPRS Explain

(E)GPRS Signaling



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(E)GPRS Signaling

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RN20022EN20GLA0

(E)GPRS Signaling

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Module objectives

After completing this learning element, the participant will be able to:

Theory:

• Explain the (E)GPRS main Mobility Management and Session Management procedures

• Understand the concept behind Routing Area design

• Explain Paging coordination

• Explain the concept of a Temporary Block Flow TBF

• Describe the different identities used on different interfaces

• List different categories of MSs



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(E)GPRS Signaling

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(E)GPRS Procedures - Content

GPRS Mobility Management (GMM) and GMM State Management

• GMM States

• GPRS attach

• GPRS detach

• Routing Area updates

Session Management

• PDP context activation/modification/deactivation

Temporary Block Flow

• Radio Resource states

• TBF establishment

• RLC/MAC Header

Categories of MSs



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GPRS Mobility Management - Mobile States

The GPRS Mobility Management (GMM) is a protocol which manages Security (ciphering, P-TMSI allocation) and GMM States.

State Transition are based on Signaling procedures and timers configured in the SGSN:

GPRS Attach:

• The MS makes itself known to the network

• The authentication is checked and the location in HLR is updated

• Subscriber Information is downloaded from the HLR to the SGSN

• State transition Idle to Ready

• Normal procedure may take 5 seconds

Session Management (SM):

• before any PDP context activation the MS has to be GPRS attached.

• If the MS is detached any existing active PDP context is automatically deactivated

Timers controlling state transitions

• READY Timer (set in SGSN, default 44s)• MOBILE REACHABLE Timer (default about 2 hours – recommendation: bigger than 2x the

Periodic Routing Area update timer)



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Attach Procedure

The GPRS Attach procedure establishes a GMM context between MS and SGSN. There are

two types of attach possible:

• a normal GPRS Attach, performed by the MS to attach the IMSI for GPRS services only

• a combined GPRS Attach, performed by the MS to attach the IMSI for GPRS and non-GPRS

services (in case of Gs being implemented)

The Gs interface enables two functions:

• Paging Coordination (needed for DTM operation and additionally any MS will not loose CS

pagings, while in packet transfer)

• Combined Mobility Management (combined attach/Location updates)

The presence of the Gs is indicated to the MS in System Information as Network Operation

Mode (NOM) parameter (sometimes called Network Mode of Operation, NMO)

• NMO 1: Gs is present

• NMO 2: Gs is not present

Gb

Gs is option

MSC/VLR

BSS

A

SGSN



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Paging coordination

Paging Coordination can be provided in

• NMO 1 with Gs:

CS pagings for a IMSI and GPRS

attached MS would run through Gs-Gb

• NMO 2 without Gs by BSC:

Any CS paging would come through A.

BSC has to check if there is ongoing TBF

for each incoming CS paging

Gb

Gs

MSC/VLR

BSC

A

SGSN

Gb

No Gs

MSC/VLR

BSC

A

SGSN

NMO 1

NMO 2

The “Paging coordination in BSC” feature

- requires PCU2 functionality

- generates a lot of signaling between the PCUs and the BCSUs, an overload mechanism is implemented



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Paging coordination

NMO 2 without Gs handled by BSC:

CS Paging Coordination in NMO II means that MS in Packet Transfer Mode can be paged

for CS connection with Packet Paging Request messages sent on PACCH

• CS paging is received via A interface (no Gs between MSC and SGSN)

• CS Paging makes MS to abort PS session before CS connection setup

• If support for DTM (from MS and network) is given, the session can be continued duringcall

Gb

no Gs

MSC/VLR

A

SGSN

NMO 2

BSCIf MS transfers packets, paging

is sent on PACCH and PCH

If MS transfers packets, paging

is sent on PACCH and PCH

If MS does not transfer packets,

paging is sent on PCH as usual

If MS does not transfer packets,

paging is sent on PCH as usual

PACCH

PCHCS paging

“Paging coordination in BSC” feature is active:



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Attach procedure in brief:

MS initiates by sending Attach Request (here no Gs so normal GPRS attach only)

- If network accepts Attach Request it sends Attach Accept with P-TMSI and RAI

- If network does not accept Attach request it sends Attach Reject

- MS responds for Attach Accept message with Attach Complete (only if P-TMSI changes)

(E)GPRS Attach Process – GPRS Attach



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(E)GPRS Attach Process

Attach Request

( old [LAI,P-TMSI] ) Identification Request

( RAI, P-TMSI )

Identification Response

( cause, IMSI, authentication data )

Update GPRS Location

( IMSI, SGSN-no., SGSN-IP-address )

Authentication

Insert Subscriber Data

( IMSI, PS subscription information )

Cancel Location( IMSI, type=update )

Cancel Location Ack

( )

Insert Subscriber Data Ack

Update GPRS Location Ack

( HLR number )Attach Accept

( new P-TMSI, new RAI )

Attach Complete

( )

MS New SGSN Old SGSN HLR



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Suspend/Resume procedure

A GPRS MS when attached will be temporarily suspended from GPRS services, when in

dedicated mode (at least as long no support for simultaneous CS and PS traffic is given byMS or network (Dual Transfer Mode-DTM)).

MS gives SUSPEND indication on SDCCH to BSC. BSC forwardens it to PCU and PCU to

SGSN.

The MS‘s identity TLLI and its current location RA is delivered with this message. The SGSN

confirms the reception of this message by either returning SUSPEND-ACK or SUSPEND

NACK. A SUSPEND request is not acknowledge, if for instance the MS is unknown.

A packet switched service can be resumed, if the BSS sends the PDU RESUME to the

SGSN (during call release). The TLLI, the routing area of the MS and the Suspend

Reference Number are included in this PDU. Under normal conditions, the SGSN returns a

SUSPEND-ACK PDU, otherwise a SUSPEND-NACK is returned to the BSS.

If the suspension is not successful, the MS would initiate a Routing Area Update in order to

resume GPRS services.Suspension will happen whenever the MS enters dedicated mode (not when DTM is

supported) while GPRS attached.

- for SMS

- for Location Update

- for call

- for …



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Suspend/Resume procedure

SUSPEND

( TLLI, Routing Area )

SUSPEND-ACK

( TLLI, Routing Area,

Suspend Reference Number )

RESUME

RESUME-ACK

( TLLI, Routing Area )

( TLLI, Routing Area,

Suspend Reference Number )

Call Control for a cs service

RR Suspend

condition for GPRS

suspension disappears

RR Channel Release

MS enters de-

dicated mode

MS leaves de-

dicated mode

Routing Area Update Request if resume was not successful

( resume )

MS BSS

SGSN

MSS/VLR

RR radio resource

TLLI temporary logical link identifier



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Detach Process

GPRS Detach procedure is used for the following two purposes:

• a normal GPRS Detach

• a combined GPRS Detach (GPRS/IMSI detach, MS originated in case of Gs)

MS is detached either explicitly (by message for example when MS is powered off) or implicitly

(upon timer expiry for example when battery runs empty):

• Explicit detach: The network or the MS explicitly requests detach.

• Implicit detach: The network detaches the MS, without notifying the MS, a configuration-

dependent time after the mobile reachable timer expired (settings in SGSN).



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(E)GPRS Detach Process

MS initiated detach (here combined detach with Gs interface)

NW initiated detach (here with Gs, MS remains IMSI attached)

HLRMS BSS GGSNSGSN MSC/VLR

3. Delete PDP Context Request

1. Cancel Location

4. GPRS Detach Indication

2. Detach Request

6. Cancel Location Ack

3. Delete PDP Context Response

5. Detach Accept

3. IMSI Detach Indication

2. Delete PDP Context Response

1. Detach Request

2. Delete PDP Context Request

5. Detach Accept

MS BSS GGSNSGSN MSC/VLR

4. GPRS Detach Indication

GMM signalling

GMM signalling



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Routing Area

Routing Area (RA):

• One RA is a subset of one and only one Location Area (LA)• Without “Multipoint Gb Interface” feature one RA is served by only one SGSN, but one SGSN

can serve several RAs

• With “Multipoint Gb Interface” feature one RA can be served by several SGSNs, anyway oneMS will allways be attached in only one SGSN

• For simplicity, one LA can contain one RA

• Too big LA/RA increases the paging traffic, while too small LA/RA increases the signaling forLA/RA Update

• Routing Area Identity (RAI) = Location Area Identity (LAI) + Routing Area Code (RAC)

Location Area (LA)

Routing Area (RA) SGSN

MSC/VLR

GS Interface



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Combined Mobility Management

LA 1

LA 2

RA 11

RA 13

RA 12

RA 22

RA 21

MS classA or B

I haveto

indicatea new

LA andRA

SGSN

MSC/VLR

Gs

C o m

b i n e d

l o c a t i o n u p d a t e

LA updateinternally

SAVINGS:

• Combined

GPRS/IMSI attach

and detach

• Combined RA/LA

update

• Circuit switched

services paging

via GPRS network

• Non-GPRS alerts

• Identification

procedure

• MM information

procedure



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Routing Area

The Routing Area Update procedure can be:- a normal Routing Area Update

- a combined Routing Area Update (in case of Gs)

- a periodic Routing Area Update

The Routing Area Update is only initiated by the MS once the MS is GPRS attached.

Routing Area Update AcceptRouting Area Update Accept (PDCCH)

Location update request (SDCCH)

Routing Area Update complete (PDCH)

Location Update Accept (SDCCH)

Channel Release (SDCCH)

Routing Area Update Request

Routing Area Update Request (PDTCH)

Read System information message (BCCH)

MS BSS SGSN

MSC

Location area Update and Routing Area update at LA/RA border (no Gs):



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MS BTS BSC New SGSN

Routing Area Update

Request (PDTCH)

Routing Area Update

RequestRouting Area Update

Request

Routing Area Update

Complete (PDTCH)

Routing Area Update

Complete

Routing Area Update

Complete

Routing Area Update AcceptRouting Area Update

Accept (PDTCH)

Routing Area Update

Accept

RA Update

New SGSN sends ‘context req’ to old SGSN

Old SGSN sends response and starts tunneling data to new SGSN (if there is any data)

New SGSN sends ‘Update PDP context request’ to GGSN for any active PDP context

New SGSN informs HLR about SGSN change by sending ‘Update location’

HLR provides Subscriber data to SGSN

HLR sends ‘Cancel location’ to old SGSN.

With Gs interface the SGSN would initiate the Location Area update towards the MSS (when the

Location Area change took place)



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The PDP (Packet Data Protocol) Context is mainly designed for two purposes for the

terminal.

- Firstly PDP Context is designed to allocate a Packet Data Protocol (PDP) address,

either IP version 4 or IP version 6 type of address, to the mobile terminal.

- Secondly it is used to make a logical connection with QoS (Quality of Service) profiles,

the set of QoS attributes negotiated for and utilized by one PDP context, through the

GPRS network (from MS to GGSN)

Session Management - Establishing a PDPContext

P D P C o n t e x t R e

q u e s t

155.1 31

. 3 3.55



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Session Management - Establishing a PDPContext

MS SGSN GGSN

1. Activate PDP Context Request

2. Security Functions (optional)

3a. Create PDP Context Request

3b. Request PDP Context Activation4. Activate PDP Context Accept

SM signallingGTP signalling

GTP GPRS Tunnel Protocol

PDP Context Activation

This procedure is initiated by the MS (mobile terminated PDP activation currently notimplemented). The PDP context contains QoS and routing information enabling datatransfer between MS and GGSN. PDP Context - Activation and - Deactivation takesabout 2 seconds (can be longer).

Like GMM procedures the messages for SM procedures are exchanged on GPRSresources.

GMM signalling



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Session Management – PDP contextDeactivation and Modification

MS SGSN GGSN

1. Deactivate PDP Context Request

2. Security Functions (optional)

3a. Delete PDP Context Request

3b. Delete PDP Context Response4. Deactivate PDP Context Accept

SM signallingGTP signalling

The Deactivation of a PDP context can be initiated by MS (as seen below) ornetwork (in case of inactivity for example). PDPs can only be active as long as the MSis attached. Any kind of detach (with detach procedure or timer expiry in SGSN) willdeactivate any active PDP context for a certain UE.

Additionally it is possible to modify QoS parameters related with one active PDPcontext with PDP context modification procedure. This procedure will be initiated bythe SGSN, for example when a MS changes from 3G or LTE (where better QoSsupport is given) to the (E)GPRS network

GMM signalling



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HLR QoS Profile

Reliability

ClassGTP Mode

LLC Frame

Mode

LLC Data

Protection

RLC Block

Mode

1 Acknowledged Acknowledged Protected Acknowledged

4 Unacknowledged Unacknowledged Protected Unacknowledged

5 Unacknowledged Unacknowledged Unprotected Unacknowledged

For real-time traffic, the QoS profile also requires appropriate settings for delay and throughput.

2 Unacknowledged Acknowledged Protected Acknowledged

3 Unacknowledged Unacknowledged Protected Acknowledged

Traffic Type

Non real-time traffic, error-sensitive

application that cannot cope with data

loss.

Real-time traffic, error-sensitive

application that can cope with data loss.

Real-time traffic, error non-sensitive

application that can cope with data loss.


application that can cope with infrequent

data loss.


application that can cope with data loss,

GMM/SM, and SMS.

usage of Rel 97/98 Reliability Classes QoS parameter 3GPP TS 03.60 (Rel 98)

Precedence Class Delay Class

Peak throughput Class

Mean throughput Class

A GPRS Subscriber profile describes a service in terms of QoS parameters. The GPRS subscription is

stored in the HLR and delivered towards the current SGSN. When a Service is activated the network isrequested to provide a bearer with the described characteristics. Correspondingly the network will use Ack

or Nack mode on the different interfaces for example.

Reliability Class



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HLR QoS Parameters

HLR parameters define if LLC or RLC

protocol work in Ack or NACK mode.

GPRS introduced Rel 97/98 attributes.

With UMTS introduction a new set of

attributes has been defined in Rel 99,

which is common for UMTS and GPRS.

In practice only reliability classes 2 and 3

work today properly from the end user

satisfaction perspective and can thus be

commercially used.

There are some terminals in the market

that can not support the usage of

reliability class 2.

5'yes'

Reliability

class

1, 2, 3, 4'no'Delivery of

erroneous SDUs

54*10- 3

Reliability

class

1, 2, 3, 410- 5Residual bit error

ratio

4, 510- 3

310- 4

Reliability

class

1, 210- 6SDU error ratio

NameValueValueName

Derived from R97/98

Attribute

Resulting R99 Attribute

SDU error ratio:

<= 5*10- 4 : RLC ack

> 5*10- 4 : RLC unack



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TBF Concept3GPP 43.064

Class A

(DTM)

Class B

Packet

Transfer

Idle/

Packet

Idle

Packetaccess

Dedicated

Mode

RRrelease

TBF(s)

released

DTM assignment

DTM Release

RRestablishment

Dual

Transfer

Mode

The Temporary Block Flow (TBF) is active when the MS is in Packet Transfer mode

or in DTM (dual transfer mode) State.

The TBF is identified by a Temporary Flow Identifier (TFI) which identifies

unidirectional transmission resources on one or several PDCHs. They comprise a

number of RLC/MAC blocks, which are used to carry one or several upper layer PDUs

or RLC signalling. The TFI is allocated only for the duration of the transmission, i.e. it is

temporary.

Radio Resource (RR) States are defined between the MS and PCU



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RR (Radio Resource states) and GMM states

StandbyReady

Once the MS is in GMM standby (and of course GMM idle) the MS can not be in

packet transfer mode.

3GPP 43.064

Correspondence between RR operating modes and MM states (non-DTM capable MS) .

RR BSS Packet transfermode

Measurementreport reception

No state No state

RR MSPacket transfer

modePacket idle mode

Packet idle

modeGMM (NSS

and MS)

Standby

RR BSSDual

transfer

mode

Dedicated

mode

Packet

transfe

r mode

Measurement

report

reception

No

stateDedicate

d mode

No state

RR MSCS idle and packet idle

CS idle

and packet

idle

GMM

(NSS and

MS)

Ready

Correspondence between RR operating modes and MM states (DTM capable MS) .



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Temporary Block Flow

DL TBF

• Network starts and releases DL TBFs by simply sending an assignment (eg when MS listens to its paging)

• FBI (Final Block Indicator) indicates the last block in a DL TBF

• The SGSN has to know the cell of the MS and has to provide this information to PCU, so that the DL TBF

can be established (the MS has to be in GMM ready state)

Once a UL TBF is running a DL TBFs can be established as concurrent TBF on the PACCH (as RLC

signalling on PACCH).

UL TBF

• MS requests for (E)GPRS resources on the RACH

• Then the MS gets an UL TBF assignment indicating the USF per allocated PDCH, USF granularity,

RTSLs and the frequency

• When TBF is finished the MS indicates this by starting the countdown procedure (The MS indicates the

number of remaining RLC blocks in its buffer)

Once a DL TBF is running an UL TBFs can be established as concurrent TBF on the PACCH (as RLC

signalling on PACCH)

BSC/PCUBSC/PCU

Uplink TBF (+ PACCH for downlink TBF)

Downlink TBF (+ PACCH for uplink TBF)



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Establishing a DL TBF and Sending Data

Packet Control Ack (for TA)

Packet Polling

Packet Downlink Assignment

Data / Signalling

Ack / Nack

BTSBTS

PACCH

PACCH

PACCH

Immediate Assignment for DL TBF

AGCH

PDTCH

PACCH

PACCH

Data

PDTCH

MSMS

TA Timing Advance



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Multiple Mobiles and Downlink Transmission

TFI 2

TFI 5

TFI 3

TFI = 2

Several MS may have ongoing DL TBF on the same RTSL. The TFI included in the

downlink RLC Block header indicates which mobile is the receiver of the data (or

signalling).

There is one RLC/MAC block every 20 ms.

Scheduling of signalling or data for different MS is performed by the PCU.

DL Radio Block

BTSBTS



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Establishing an UL TBF and Sending Data

Channel Request

Immediate Assignment for UL TBF

UL Data or Signaling

Signaling + Ack/Nack

Final UL Data

Final Ack/Nack

Packet control Ack

RACH

AGCH

PDTCH / PACCH

PACCH

PDTCH

PACCH

PACCH BTSBTS



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• Maximum of 7 Mobiles can be queued in the uplink per RTSL (there are 3 bits and one

value is reserved for the MSs that have DL TBF to transmit the PACCH)

• Mobile transmission is controlled by USF (Uplink State Flag) sent in DL RLC/MAC blocks.

The MS is going to send in the next UL block (or next 4 UL Blocks) when it finds its USF

value in DL

• In standard implementation one MS has to monitor the DL Blocks for each assigned RTSL

• With EDA (Extended Dynamic Allocation) the MS will monitor only one DL RTSL and if it

finds its USF it can transmit on all assigned UL RTSL in parallel

Multiple Mobiles and Uplink Transmission

USF = 1USF = 2

USF = 3

USF = 3(in MAC header)

BTSBTS

DL Radio Block

This MS is allowed

to transmit the

next UL block

(or 4 UL Blocks)



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USF granularity

There are 2 ways to allocate UL resources to one MS in (E)GPRS:

USF granularity 1 implemented with PCU1 and USF granularity 4 with PCU2:

USFUSF……

USFUSFRadio Block 4

USFUSFRadio Block 3

USFUSFRadio Block 2

USFUSFRadio Block 1

76543210

USFUSF……

Radio Block 4

Radio Block 3

Radio Block 2

USFUSFRadio Block 1

76543210

U S F g r anu l ar i t y

1

U S F g r anu l ar i t y

1

U S F

g r anu l ar i t y 4

U S F

g r anu l ar i t y 4



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Extended UL TBF mode EUTM release

Data block with CV = 0

EUTM delay timer starts

Schedule USF turn for MS

UL dummy control block



EUTM delay timer expiresPACKET UL ACK/NACK (FAI=1,

Polling=YES)

PACKET UL ACK/NACK (FAI=0,

Polling=NO)

PACKET CONTROL ACKUL TBF terminated

Data block with CV = 1

U L

T B F

e x t e n d e d

s t a t e

Short description:• Countdown procedure is ongoing.

EUTM supporting mobile is allowed torecalculate Countdown Value CVduring procedure, if it gets more data tosend. PCU notices this by monitoringBlock Sequence Number (BSN) andCountdown value (CV) sent by MS.

• After receiving CV=0 block PCU startsUL extended state. It sends PacketUplink Ack/Nack message to MS withno Final Ack Indicator (FAI) on, butacknowledging all received blocks.

• During UL extended state PCUschedules USFs for MS accordingadjustable scheduling rate parameter.If MS has no new data to send it sendsUL dummy control blocks on its

sending turn.

• When UL extended state ends,according adjustable release delayparameter, PCU sends Packet Uplink Ack/Nack message to MS with Final Ack Indicator (FAI) on.

UL TBF Schedule Rate Ext



MS BSS



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Radio Link Control (RLC)/ Medium Access Control(MAC) Header

Switching between PACCH and Data is managed with the Payload Type field in the

RLC/MAC header. The RLC/MAC header is different for UL and DL and for EGPRS.

The presented Headers are for GPRS. In case of EDGE there are several header types

defined, but the fields are almost the same (with one exception: in GPRS there is no

indication about the used CS (CS 1 to 4) but in EGPRS there is an indication of the used

MCS (MCS 1 to 9) and PS (Puncturing Scheme 1 to 3).

Complete description can be found in 3GPP 43.064.

Abbreviations of the fields in the RLC/MAC header:

E Extension

FBI Final block indicator (last block or not)

R Retry bit (if several access burst have been sent or not)

PFI Packet Flow Identifier Indicator (if PFI field is present or not in the header)

PR Power Reduction (DL only and not implemented)

PT Payload Type (signalling or data)TI TLLI Indicator (TLLI present or not)

RRBP Relative Reserved Block Period (when to sent the UL PACCH)

SI Stalled indication (if UL RLC numbers are sufficient)

S/P Supplementary/Polling

LLC

SNDCP

IP

TCP/UDP

APP

RLC

MAC

GSM RF



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E

Downlink RLC Data Block with MAC Header

USF - Uplink State Flag FBI - Final Block Indicator

TFI - Temporary Flow Indicator BSN - Block Sequence Number

BSN

8 7 6 5 3 2 14 Bit-NoUSFS/PPayload Type RRBP

TFI FBIPR

Length Indicator EM

Length Indicator EM

RLC data

MAC

header octet 1

octet 2

octet 3

octet M+1

octet M

octet N-1

optional

octets

RLC

header

RLC

data

unit



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Uplink RLC Data Block with MAC Header

MACheader

RLC

header

BSN

.

.

.

8 7 6 5 3 2 14 Bit-No

Payload Type Countdown Value

TFI TI

Length Indicator

E

EM

Length Indicator EM

RLC data

Spare bitsSpare bits

octet 1

octet 2

octet 3

octet M+5

octet M

octet N-1octet N(if present)

Optional

octets

RLC

dataunit

TLLI

SI R

octet M+1

octet M+4

PIspare

PFI E

BSN - Block Sequence Number= RLC block number TFI - Temporary Flow IndicatorCountdown value - used to calculate number of remaining RLC blocksTLLI Temporary Logical Link Identifier (identity of MS)



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(E)GPRS Identities

Air A-bis A-ter A

GbGs

TFI

TLLI (Temporary Logical Link Identifier)

IMSI or P-TMSI

-Temporary Flow Identifier (TFI) is allocated by PCU as long of TBF is running

-The MS has independent TFI for UL and DL TBFs in case of UL and DL TBFs are active.

-Temporary Logical Link Identifier (TLLI) in UL is chosen by MS (based on P-TMSI or

random TLLI in case of MS has no P-TMSI, then MS has to do the attach procedure)

-TLLI is carried in the RLC protocol to PCU in UL TBF and forwarded to the SGSN in

BSSGP protocol. There are 2 ways to transfer the TLLI,

-It can be part of the RLC header in case of one phase access type

-It can be transferred as part of RLC control message (Packet Resource Request)

for other access types (on PACCH)

-TLLI is carried in BSSGP protocol by SGSN to PCU in DL TBF and PCU can check if

there is already UL TBF running or an assignment has to be sent

MS BTS BSC

SGSN

TC

PCU

MSC



RN20022EN20GLA0

(E)GPRS Signaling

38


BSC

BTS

• Class C Packet only(Can not be attached in CS and PS core)

• Class B Packet and Speech (not at same time)(can be attached in CS and PS core, but can only make call or sent data)

• Class A Packet and Speech at the same time(support for Dual Transfer Mode [DTM] is given)

(E)GPRS Mobile Terminal Classes



RN20022EN20GLA0

(E)GPRS Signaling

39


(E)GPRS Multislot Classes

Type 1

Multislot Classes 1-12- Max 4 DL or 4 UL TSL (not at same time)

- Up to 5 TSL shared between UL and DL

- Minimum 1 TSL for frequency change

- 2-4 TSL freq. change

Multislot Classes 19-29

- Max 8 downlink or 8 uplink

(not at same time)

- 0-3 TSL for frequency change

High Multislot Classes 30-45 (3GPP Rel-5)

- Max: 5 DL or 5 UL (6 UL+DL) or

- Max: 6 DL or 6 UL (7 UL+DL)

Type 2Multislot Classes 13-18

- simultaneous receive & transmit

- max 8 DL and 8 UL

(Not available yet, difficult RF design)

DL

UL

1 TSL for Frequency Change

DL

UL

1 TSL for Measurement

DL

UL

DL

UL

1

1 2 3 4 5 6 70

1 2 3 4 5 6 70



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(E)GPRS Signaling

40


DA/EDA Allocation

• Dynamic Allocation: Multislot MS needs to monitor UplinkState Flag (USF) on each timeslot allocated in Uplinkdirection. Max UL allocation is 2 RTSL.

• Extended Dynamic Allocation: Multislot MS monitorsUplink State Flag (USF) until it receives it on one timeslotand transfers data on UL assigned resources (numberdepends on MS class)

USF gives permission to send inthe corresponding uplink slotduring the next block period

USF gives permission to send inthe corresponding uplink slotduring the next block period

USF gives permission to send inthe corresponding and all highernumbered allocated uplink slots

during the next block period.

USF gives permission to send inthe corresponding and all highernumbered allocated uplink slots

during the next block period.

0 1 2 3 4 5 6 7

0 1 2 3 4 5 6 7

T

USFUSF

T

0 1 2 3 4 5 6 7

0 1 2 3 4 5 6 7

T

USF

TT T

0

50

100

150

200

250

300

350

GPRS GPRS CS3/4 EDGE

k b i t / s S11.5

S12

Peak uplink throughput



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(E)GPRS Signaling

41


Dual Transfer ModeSupported MS Multislot Classes

DTM Multislot Classes• Class 5: Voice & 1 + 1

• Class 9: Voice & 2 + 1

• Class 11: Voice & 2 + 1 or 1 + 2

(2 in UL only with with EDA)

Downlink radio slots: 0 1 2 3 4 5 6 7

Uplink radio slots: 0 1 2 3 4 5 6 7

DTM Class 5,9,11 PS CS

2+2=4 PS CS

DTM Class 5,9,11 CS PS

2+2=4 CS PS

DTM Class 9,11 PS PS CS

3+2=5 PS CS

DTM Class 9,11 PS CS PS

3+2=5 CS PS

DTM Class 11 PS CS

2+3=5 EDA PS CS PS

DTM MS Class 31,32 PS PS PS CS

HMC PS CS

DTM MS Class 31,32 PS PS CS PS

HMC CS PS

DTM MS Class 32 PS PS CS

HMC, EDA PS CS PS

Will be supported

as class 5,9, or 11



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(E)GPRS Signaling

42


(E)GPRS Multislot Classes - Dual carrier

A key part of the evolution of EDGE is the utilization of more than one radio frequency

carrier. This overcomes the inherent limitation of the narrow channel bandwidth of GSM.Using two carriers enables the reception of twice as many radio blocks simultaneously or,

alternatively, the original number of radio blocks can be divided between the two carriers

enabling a bigger flexibility, resulting in trunking gain.

Downlink dual carrier (DLDC) is only for DL and EGPRS, not GPRS!

- requires optional support of MS (3GPP Rel 7)

- existing Multislot classes are used (MS indicates additionally support for DLDC)

- requires re-dimensioning of EGPRS resources

- doubles downlink peak throughput up to 1184 kbps (but not for all Multi-slot classes)

- One of the carriers can be the BCCH carrier and the other on a TCH/TRX with frequency

hopping

- since S15 DLDC allows for individual link adaptation on the different carriers

- EDA is not supported with DLDC

- Asymmetric allocations are possible.



(E)GPRS Signaling


(E)GPRS Multislot Classes - Dual carrier

Example: Multislot class 12, Dual carrier, with DL (8 TSL) plus UL (1 TSL) TBFs

Neighbour cell

measurements (Rx)

UL bursts, Tx

DL bursts, Rx 2

DL bursts, Rx 11 2 3 4 5 6 70

1 2 3 4 5 6 70

IDLE

IDLE

1 2 3 4 5 6 70 1 2 3 4 5 6 70

1 2 3 4 5 6 70 1 2 3 4 5 6 70

02 rn20022en20gla0 (e)gprs signalling

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