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UMTS RADIO RESOURCE CONTROL 3GPP TS 25.331

1. FUNCTIONAL ENTITIES OF RRC LAYERS are

RFE:

y Routing of higher layer msgs to different MM/CM entities is handled by RFE (routing functionentity).

BCFE:

y Broadcast function handled by BCFE (broadcast control function entity).BCFE is used to deliverRRC services which are required at the GC-SAP. It can also use lower layer services TR-SAP &

UM-SAP.

PNFE:

y Paging of UEs that do not have RRC function controlled by PNFE (Paging & Notification functioncontrol entity).It is used to deliver RRC services that are required at the NT-SAP. It can also uselower layer services TR-SAP &UM-SAP.

DCFE:

y Dedicated control function entity handles all functions specific to one UE. It used to deliver RRCservices which are required at theDC-SAP. It can also use lower layer services TR-SAP / UM-

SAP& AM-SAP.

TME:

y Transfer Mode Entity It handles Mapping b/n different entities inside the RRC layer & SAPsprovided by RLC.

SCFE:

y Shared control Function Entity controls allocation of PD-SCH & PU-SCH using lower layer servicesof UM-SAP/AM-SAP.

2. RRC FUNCTIONS & SERVICES PROVIDED TO UPPER LAYERS:

Broadcast of Information Related to AS & NAS

Establishment / maintenance/Release of RRC connection b/n UE &UTRAN

Estabilishment, Reconfiguration & Release of RadioBearers.

Assignment, Reconfiguration &Release of Radio Resources for RRC connection.

RRC connection of Mobility functions.

Control of Requested QOS.

UE measurement reporting & control of reporting.

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Outer Loop Power Control.

Control of Ciphering.

Paging.

Initial cell selection & cell Re-selection.

RRC msgs integrity protection.

RRC services provided to Upper Layers

General control

Notification control.

Dedicated control.

RRC layer provides signaling connection to upper layer for exchange of information flow

The signaling connection is AM link b/n the User network & Core Network.

Services Expected from Lower Layers:

Services expected from Layer 1&2:

They are providing by L1 ctrl from PHY layer & L2 ctrl from RLC MAC.

Signaling Radio Bearers:

The Radio Bearers available for usage by RRC msgs using RLC-TM, RLC-UM&RLC-AM on the

DCCH & CCCH are specified in the following (selection of RB by RRC- UE&UTRAN)

1. RB0 shall be used for RRC msgs sent on CCCH (UL: RLC-TM, DL: RLC-UM)

2. RB1 shall be used for RRC msgs sent on DCCH when using RLC-UM.

3. RB2 shall be used for RLC msgs sent on DCCH when using RLC-AM (except for higher layer NAS

signaling).

4. RB3 &optionally RB4 shall be used for RRC msgs carrying higher layer (NAS) signaling & sent

on DCCH in RLC-AM.

5. RB5-RB31 may be used for RRC msgs on the DCCH sent in RLC-TM

RRC Protocol States:

Overview of RRC states & State Transitions (UTRA & GSM mode)

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The RRC states in UTRA connected Mode source transition b/n UTRA connected mode & GSM

connected mode and also transition b/n UTRA connected mode & GSM/GPRS packet mode and

UTRA connected to IDLE mode.

The RRC connection is defined as a point to point bi-directional connection b/n RRC peer entities

in the UE & UTRAN characteristic by the allocation of U-RNTI(Radio Network TransactionIdentifier).

Processes in UE mode/State:

1. UE Idle mode.

2. UTRA RRC connected mode. This mode consist of several states

a. URA_PCH or CELL _PCH state. It performs the following action

If the UE is in service area:

y Maintain up to date system information as Broadcast by the serving cell.y Perform cell Re-selection process.y Perform a periodic search for higher priority PLMNs.y Monitor the Paging occasions according to DRX cycle & receive paging information on PCH cycle.y Perform Measurement process according to measurement control information.y Maintain up to date BMC data if it supports CBS (cell broadcast services).y Run timer T305 for a periodical URA update if the UE is in URA_PCH or for periodical cell update

if the UE is in CELL_PCH.

If the UE is in out of service area it performs

y Cell Re-selection process.y It runs timer T316 (out of service area)& T305(entering cell URA PCH state)

b. CELL_FACH state:

If UE is IN SERVICE AREA

y DCCH & DTCH are available.y Run timer T305 (periodical cell update).y Listen to all FACH Transport chs assign to this UE.If the UE is in out of service area it performs:

y Cell Re-selection process.y Run timer T305 (periodical cell update) & T317(cell update when Re-entering in service)or

T307(Transition to idle mode)

C.CELL_DCH state:

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In the CELL_DCH performs following action (ifDTCH &TCH available)

y Read system information Broadcast on FACH.y Perform Measurement process according to measurement control information.

RRC PROCEDURES: