RRC_R99

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Radio Resource Con

trolTS 25.331 (R99)

Kevin Kim

[email protected]

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Contents

1. RRC Layer Architecture

2. RRC Service States

3. RRC Functions & Signalling Procedures

1) Broadcast of System Information

2) Paging

3) RRC Connection

4) Control of RB, Tr CHs & Phy CHs

5) Control of Security Functions

6) Measurement Control & Reporting

7) RRC Connection Mobility Functions

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1. RRC Layer Architecture

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Entity Description

RFERouting Function Entity

- handles Routing of higher layer messages.

BCFE

Broadcast Control Function Entity

- handles Broadcasting of System Information.

- at least one BCFE in the RNC.

- uses BCCH or FACH via Tr-SAP.

PNFE

Paging and Notification Control Function

Entity- controls Paging of UEs in Idle Mode.

(ifRRC Connection exists, Paging by DCFE)

- at least one PNFE in the RNC.

- uses PCCH via Tr-SAP.

DCFE

Dedicated Control Function Entity

-handles all functions specific to one UE.

- uses mostly Acknowledged Mode SAP(AM-SAP).

- uses Unacknowledged Mode SAP(UM-SAP) when

RRC Connection Release, or Tr-SAP when Cell

Update.

TME

Transfer Mode Entity

- handles the mapping between theRRC entitiesand the SAPs.

RRC Layer Architecture

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Idle Mode

Connected Mode

CELL_DCH CELL_PCH

URA_PCHCELL_FACH

UE Modes and RRC States

Mode(State) Description

Idle Mode

- performs PLMN Selection, Cell Selection

- receives System Information, Cell Broadcast Message.

- UE is identified by NAS Identities(IMSI, TMSI, P-TMSI).

- to Connected Mode when it transmits a request to establish an RRC Connection.

CELL_DCH

-UE is known by its Serving RNC on a cell or active set level.

- performs Measurement and sends Measurement Report.

- read System Information broadcast on FACH.

-act on RRC messages received on DCCH/BCCH.

- battery consumption : 200~300mA

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CELL_FACH

- uses RACH, FACH for transmitting both signalling messages and small amounts of user plane

data.

-read System Information on BCH.

- performs Cell Reselections, and sends a Cell Update message to the RNC.

- RNC knows the UE location on a cell level.

- C-RNTI(Cell Radio Network Temp Identifier) separates UEs from each other in a cell.

- battery consumption : 100~150mA

CELL_PCH

- read System Information on BCH.

- RNC knows the UE location on a cell level only via the PCH(Paging Channel).

- UEs supporting Cell Broadcast Service can receive BMC message.

- moves to the CELL_FACH to execute the Cell Update procedure.

- battery consumption : less than 5mA (because DRX)

URA_PCH- similar to the CELL_PCH, but UE does not execute Cell Update after Cell Reselection.

-if URA changes after CR, UE performs URA Update(moves to CELL_FACH).

vOverlapping URA

One cell can belong to one or many URAs.

It is needed to avoidping-pong effects.

Cell1URA1URA2

Cell2URA1URA3

Cell3URA3URA4

No URA Update

URA Update(URA1 URA3)

No URA Update

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Before State After State

Idle Mode RRC connection Establishment

Connected Mode

(CELL_FACH /

CELL_DCH)

CELL_DCH

RRC connection Release Idle Mode

All Dedicated Channels Release CELL_FACH

via explicit Signalling

(radio bearer setup, radio bearer reconfiguration, radio bearer

release, transport channel reconfiguration, physical channel

reconfiguration, etc)

CELL_PCH / URA_PCH

CELL_FACH

RRC connection Release Idle Mode

Dedicated Physical Channel is established CELL_DCH


(cell update confirm, radio bearer reconfiguration, etc) CELL_PCH


(URA update confirm, radio bearer reconfiguration, etc)URA_PCH

CELL_PCH Paging from UTRAN, Uplink Access CELL_FACH

URA_PCH Paging from UTRAN, Uplink Access CELL_FACH

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3. RRC Functions & Signalling Procedures

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Broadcast of System Information

Paging

Initial Cell Selection & Reselection in Idle mode

RRC Connection Establishment, Maintenance &

Release

Control of Radio Bearers, Transport CHs & Physical

CHs

Control of Security Functions

Measurement Control & Reporting

RRC Connection Mobility Functions

Support of SRNS relocation

Downlink outer loop power control

Open loop power control

Cell Broadcast Service related function

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3.1) Broadcast of System Information

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v Broadcast of System Information

The broadcast system information originates from Network.

The System Information messages are sent on a BCCH logical channel, which can be mapped to

the BCH or

FACH transport channel.

One System Information message can carry either several SIBs or only part of one SIB.

v System Information Structure

Master Information Block(MIB)

give references and scheduling information to SIB and

Scheduling Block.

be sent regularly on the BCH and its scheduling is static. Scheduling Block

give references and scheduling information for additional SIB.

System Information Block(SIB)

contain the actual system information.

group together system information of the same nature.

UE UTRAN

SYSTEM INFORMATION

BCCH(TM)

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v Modification of System Information

For the SIBs with Dynamic Parameter

by SIB-specific timer(value in frames) in scheduling information.

For the SIBs with Static Parameter when SIB value tag has changed with latest read SIB value tag.

Notification from UTRAN

Idle mode, CELL_PCH and URA_PCH state

CELL_FACH state

UE UTRAN

PAGING TYPE 1PCCH (TM)

UE UTRAN

SYSTEM INFORMATION CHANGE INDICATIONBCCH (TM)

v If the UE does not find the system information block in a position, The UE shall consider the cell to be

barred.

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Type Description

MIB Supported PLMN Types, PLMN Identity, Ref to other SIB and Scheduling blocks

Scheduling Block #1,

#2References to other SIBs

SIB#1NAS System Information, CN Domain System Information, UETimers andconstants in Idle/Connected Mode

SIB#2 URA Identity

SIB#3 Cell Selection and Reselection Information, SIB#4 indicator

SIB#4 Cell Selection and Reselection Information in Connected Mode

SIB#5 Phy CHs Information, SIB#6 indicator

SIB#6 Phy CHs Information in Connected mode

SIB#7 Fast changing parameters UL interference and Dynamic persistence level

SIB#8 Static CPCH Information

SIB#9 CPCH Information

SIB#10 Dynamic Resource Allocation Control(DRAC) System Information

SIB#11 Measurement Control Information, SIB#12 indicator

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Type Description

SIB#12 Measurement Control Information in Connected Mode

SIB#13 ANSI-41 System Information

SIB#14Common and dedicated Phy CH uplink outer loop power control information (only

TDD)

SIB#15 Positioning Methods Information (e.g. GPS, Satellite)

SIB#16 Information For Handover (e.g. Radio Bearer, Tr CH and Phy CH Information)

SIB#17 Fast changing parameters for the shared Phy CHs in connected mode (only TDD)

SIB#18 PLMN identities of neighbouring cells in Idle/Connected Mode

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3.2) Paging

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v Paging (Paging Type 1)

Transmit paging information to UEs in Idle mode, CELL_PCH or URA_PCH state on the PCCH

usingTM RLC.

To trigger a Cell/URA Update procedure

To indicate change in the system information. Target is all UEs in a cell.

To establish a Signaling connection for MT calls.

Message Structure

Paging Record : Paging Cause, Choice UE Identity( IMSI/TMSI/P-TMSI or U-RNTI )

BCCH Modification Information

v UE dedicated Paging (Paging Type 2)

For One UE in CELL_DCH or CELL_FACH state using the DCCH using AM RLC.

To establish a Signaling connection for MT calls.

Message Structure

UE Information : RRC Transaction Identifier, Paging Cause

CN Information : CN Domain Identity. Paging Record Type

UE UTRAN

PAGING TYPE 1

PCCH (TM)

UE UTRAN

PAGING TYPE 2

DCCH (AM)

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3.3) RRC Connection

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v RRC Connection

A bi-directional connection between RRC peer entities on the UE and the UTRAN.

Initiated by a request from UE higher layers, or by RRC Paging Message from Network.

Only Zero or One RRC Connection between one UE and UTRAN.

v Signalling Connection

An Acknowledge Mode Link between UE and CN to transfer higher layer information in NAS.

More than one Signalling Connection between UE and CN Node, they share the same RRC

Connection.

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3.3) RRC Connection

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v RRC Connection Establishment

UE UTRAN

RRC CONNECTION SETUPCCCH (UM)

RRC CONNECTION REQUESTCCCH (TM )

RRC CONNECTION SETUP COMPLETEDCCH (AM)

Establishment Cause

Initial UE Identity(P-TMSI+RAI, TMSI+LAI or

IMSI)Move to CELL_DCH: Dedicated CH Info

Move to CELL_FACH: Common CH Info, U-

RNTI

v After RRC Connection Establishment, creates Signalling Radio Bearers (SRBs) designated by the

RB #1~4.

The SRBs can later be created, reconfigured or even deleted with the Radio Bearer Control proceduresSRB Contents

SRB #0 All Message sent on the CCCH ( UL :TM RLC, DL : UM RLC )

SRB #1 All Message sent on the DCCH and UM RLC

SRB #2 All Message sent on the DCCH and AM RLC (except Direct Transfer Message)

SRB #3 Direct Transfer Message sent on the DCCH and AM RLC

SRB #4 (Optional)Low Priority Direct Transfer Message sent on the DCCH and AM RLC

when SRB #4 is used, SRB #3 is used for High Priority Message.

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3.3) RRC Connection

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v RRC Connection Release

To release all RBs and all SRBs between the UE and the UTRAN

UE UTRAN

RRC CONNECTION RELEASEDCCH (UM)

RRC CONNECTION RELCOMPLETE

DCCH (AM/UM)

UE UTRAN

RRC CONNECTION RELEASECCCH (UM)

CELL_DCH state CELL_FACH state

v RRC Connection Re-establishment

After Radio Link failure, UE re-establish a connection.

Timers are used to control the allowed time for a UE to return to in-service-area and to execute

the re-establishment.

The re-establishment functionality is included in the Cell Update procedure

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3.4) Control of RB, Tr CHs & PhyCHs

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vOn request from higher layers, RRC performs the establishment, reconfiguration and release of RBs.

v Messages are sent on the downlink DCCH using AM or UM RLC

v The SRBs are normally set up during the RRC Connection Establishment procedure.

v TheTr & Phy CHs parameters are included in the RB procedures, but can also be configured separately.

v These procedures perform a hard handover.

v RADIO BEARER SETUP

ContainsTr CHs & Phy CHs parameters, Ciphering & Integrity info, RNTI info, activation time for

new RB.

v RADIO BEARER RECONFIGURATION

Contains parameters related to Quality of Service(QoS), reconfiguration of Tr CHs & Phy CHs.

v RADIO BEARER RELEASE

Also can include reconfiguration of Tr CHs & Phy CHs

Indicate release of Signaling connection when UE is connected to more than one CN domain

v TRANSPORT CHANNEL RECONFIGURATION

Possibly include reconfiguration of Phy CHs

v PHYSICAL CHANNEL RECONFIGURATION

) l f i

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3.5) Control of Security Functions

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v The RRC Security Mode Control procedure is used to start Ciphering and Integrity protection between

the UE and

UTRAN and to trigger the change of the ciphering and integrity keysduring the connection.

UE UTRAN

SECURITY MODE COMMANDDCCH (AM)

SECURITY MODE COMPLETEDCCH (AM)

v

Ciphering The Ciphering key is CN domain specific,

two keys(PS/CS) are used simultaneously

for one UE. the newer key is used.

executed on RLC Layer for services

using AM/UM RLC and MAC Layer for

services usingTM RLC.

PLAINTEXT

BLOCK

f8

COUNT-C DIRECTION

B EARER LENGTH

CK

KEYSTREAM

BLOCK

CIPHERTEXT

BLOCK

f8

COUNT-C DIRECTION

BEARER LENGTH

CK

KEYSTREAM

BLOCK

PLAINTEXT

BLOCK

Sender

UE or RNC

Receiver

RNC or UE

3 5) C l f S i F

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3.5) Control of Security Functions

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v Integrity Protection

The RRC layer inserts a 32-bit integrity checksum(Message Authentication Code for Integrity

Protection; MAC-I)

into most RRC PDUs.

All higher layer messages(e.g. Direct Transfer) are automatically also integrity protected.

The Integrity key is also two keys(PS/CS) are used simultaneously for one UE. the newer key is

used.

The key is generated, together with the ciphering key (CK), during the authentication

procedure.

v Only a few RRC messages cannot be integrity protected; examples are the messages exchanged during

the RRC Connection Establishment procedure.

f 9

COUNT-I DIRECTION

MESSAGE FRESH

IK

MAC -I

f 9

COUNT-I DIRECTION

MESSAGE FRESH

IK

XMAC -I

Sender

UE or RNC

Receiver

RNC or UE

3 6) M t C t l & R

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3.6) Measurement Control & Reporting

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v Measurement Control

The measurements performed by the UE are controlled by the RNC.

UE UTRAN

SYSTEM INFORMATION(SIB11)

BCCH (TM)

UE UTRAN

MEASUREMENT CONTROLDCCH (AM)

Idle mode, CELL_FACH,CELL_PCH, URA_PCH state

CELL_DCH state

Measurement Control Information Description

Measurement Identity Number

A reference number of Measurement

For UTRAN : modification or release of the measurement

For UE : measurement report

Measurement Command Set-up, Modify, Release

Measurement Type

1. Intra-Freq Measurement

2. Inter-Freq Measurement3. Inter-System Measurement

4. Traffic Volume Measurement (UL)

5. Quality Measurement (Block Error Rate of DL Tr CH)

6. Internal Measurement (UE Tx Power, Received Signal Level)

7. Positioning Measurement

3 6) M t C t l & R

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Measurement Control Information Description

Measurement Objects The objects the UE measures, and object information

Measurement Quantity The quantity the UE measures

Measurement Reporting Quantity The quantities the UE includes in the report

Measurement Reporting CriteriaThe criteria that trigger the measurement report (Periodical, Event-Triggered)

Reporting Mode AM RLC or UM RLC

3 6) M t C t l & R

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v Measurement Report

Initiated by UE to transfer Measurement Results to UTRAN when the reporting criteria are met.

Report is sent in CELL_DCH state, it is used for all measurement.

Report is sent In the CELL_FACH state, it is used only for aTraffic Volume measurement or UE

positioning measurement report.

UE UTRAN

MEASUREMENT REPORTDCCH (AM/UM)

Measurement Identity

Measurement Result

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3.7) RRC Connection Mobility Functions

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v Mobility

Keeping track of a UEs location while the UE is in UTRAN Connected mode.

1. Active Set Update

Update the active set of the connection in the CELL_DCH state.

The procedure includes functions: Radio Link Addition or Radio Link Removal. (Max number of

Radio Link : 8)

UE UTRAN

ACTIVE SET UPDATEDCCH (AM/UM)

ACTIVE SET UPDATE COMPLETE

DCCH (AM)

New U-RNTI

Integrity Check Info

Activation Time

Phy CH Informaion

Active set The set of cells with which the UE is currently connected/communicating with.

Monitored setCells that the UE has detected and is monitoring and are known to the network, theyeither don't meet the criteria or the active set is full.

Detected Set Cells that the UE has detected but are not known to the network as yet

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2. Hard Handover

Intra-Freq HOV without support of macro diversity, Inter-Freq HOV, Inter-System HOV

CELL_DCH state

No dedicated Signalling messages. But It is performed as part of the following RRC procedures:

Physical channel reconfiguration

Radio bearer establishment/reconfiguration/release

Transport channel reconfiguration

Timing re-initialized hard handover : UTRAN does not know the target SFN timing before

Hard Handover.

If IE "Timing indication" has the value "initialise, UE initiate the procedure.

Timing maintained hard handover : UTRAN knows the target SFN timing before Hard

Handover.

If IE "Timing indication" has the value maintain, UE initiate the procedure.

3 7) RRC Connection Mobility Fun

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3. Inter-System Handover from UTRAN

CELL_DCH state

The UE receives the GSM neighbour cell parameters in System Information or Measurement

Control message.

Based on the measurement report including GSM measurements, RNC makes a handover

decision.

Upon successfully completing the handover,

UTRAN shall release the radio connection and remove all context information for the UE.

UE shall clear or set variables upon leaving UTRA RRC connected mode.

BCCH: System informationor

DCCH: Measurement control

DCCH: Measurement report

Resource reservation

Resource reservation acknowledge andhandover command

DCCH: Handover from UTRAN command(GSM Handover command)

(GSM DCCH) Handover access

UE UTRAN GSM BSSMSC


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4. Inter-System Handover to UTRAN

The UE receives the UTRAN neighbour cell parameters in GSM System Information.

Upon successfully completing the handover, RNC initiates resource release from GSM BSS.

GSM BCCH or SACCH:System information

GSM SACCH:Measurement report

Resource reservation

Resource reservation acknowledgeand handover command

(GSM DCCH): Inter-System handover command(UMTS Handover to UTRAN command)

DCCH: Handover to UTRAN complete

UE UTRANGSM BSS MSC

New U-RNTI

Radio Bearer configuration

Tr CH configuration

Phy CH configuration


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5. Inter-System Cell Reselection from UTRAN

CELL_FACH, CELL_PCH, URA_PCH state

Upon successfully completing cell reselection,

UTRAN shall release all UE dedicated resources.

UE shall release all UTRAN specific resources.

6. Inter-System Cell Reselection to UTRAN

The UE initiates an RRC connection establishment procedure with cause value Inter-system cell

reselection.

Upon successfully completing cell reselection, the UE shall release all resources specific to the

other system.

IfCell Reselection fails, the UE returns back to the other system.

IfRRC Connection Establishment fails, the UE enters Idle Mode.


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7. Inter-System Cell Change Order from UTRAN

CELL_DCH, CELL_FACH state.

This procedure may be used

when no RABs are established

when the established RABs are only from PS domain.

This procedure may not be used when there is no PS signalling connection.

UE UTRAN

CELL CHANGE ORDER FROM UTRANDCCH (AM)

RB InformationTarget Cell Description

8. Inter-System Cell Change Order to UTRAN

This procedure is used by the other system to command UE to move to UTRAN cell.

The cell change order message include the identity of the target UTRAN cell.

On the UTRAN side, the UE initiates an RRC connection establishment procedure with

establishment cause set to Inter-RAT cell change order.


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9. Cell Update & URA Update

Main Purpose

To notify UTRAN after re-entering service area in the URA_PCH or CELL_PCH state.

To notify UTRAN of an RLC unrecoverable error on an AM RLC entity.

To be used as a supervision mechanism in the CELL_FACH, CELL_PCH, or URA_PCH state

by means of periodical update.

v Cell Update

Triggered by Cell Reselection, Expiry of periodic cell update time, initiation of UL data

transmission, UTRAN-originated paging, radio link failure in CELL_DCH state.

UE UTRAN

CELL UPDATECCCH (TM)

CELL UPDATE CONFIRMCCCH/DCCH (UM)

MessagesDCCH(AM)

New U-RNTI and C-RNTI

RRC State Indicator

U-RNTI

Cell Update CauseUTRAN Mobility Information Confirm

Phy CH Reconfiguration Complete

Tra CH Reconfiguration Complete

RB Release Complete

RB Reconfiguration Complete


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v URA Update

This procedure is used in the URA_PCH state.

Triggered by Cell Reselection(Only if URA Changed), Expiry of periodic URA update time.

UE UTRAN

URA UPDATECCCH (TM)

URA UPDATE CONFIRMCCCH/DCCH (UM)

UTRAN MOBILITY INFO CONFIRMDCCH(AM)

New U-RNTI and C-RNTI

RRC State Indicator

U-RNTI

URA Update Cause

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Thanks

Documents

RRC_R99