Idle Mode and Common Channel Behavior

Functions

PLMN Selection

Cell Selection / Reselection

LA / RA Update

Paging

System Information

Automatic PLMN Selection

1. Last registered PLMN

2. Home PLMN

3. PLMN priority List from “user controlled” USIM

4. PLMN priority List from “operator controlled” USIM

5. Other PLMN where RSCP > -95 dBm in random order

6. Other PLMN where RSCP <= -95 dBm in descending order

If NotAvailable

If NotAvailable

If NotAvailable

If NotAvailable

If NotAvailable

*In case HPLMN was not available for selection, it will be tried again in 30min. during national roaming (default)

Initiate Cell Synchronization

UE monitors Primary SCH code, detects peak in matched filter output

Slot Synchronization Determined ------>

UE monitors Secondary SCH code, detects SCG and frame start time offset

Frame Synchronization and Code Group Determined ------>

UE determines Scrambling Code by correlating all possible codes in group

Scrambling Code Determined ------>

UE monitors and decodes BCH data

BCH data, Super-frame synchronization determined ------>

P-CCPCH

(PSC + SSC + BCH)

UE adjusts transmit timing to match timing of BS + 1.5 Chips

Cell Synchronization complete

Cell Search

Cell Selection

These 2 parameters allow the carrier to reserve or limit access to the cells in the network;

CellReserved Reserved ; Not Reserved (If Reserved, there will be no service to UEs)

AccessClassNBarred [0-65535] (Each bit corresponds to an Access Class)

• Cell selection criteria:IF

– Squal > 0

AND

– Srxlev > 0

» then cell selection criteria are met

Squal = Qqualmeas – qQualMin

Srxlev = Qrxlevmeas – qRxLevMin - Pcompesation

Cell Selection

CPICH Ec/No [dB] measured by UE

Sent on SIB3

CPICH RSCP [dBm] measured by UE max(maxTxPowerUl - P, 0)

Cell Reselection

Cell Reselection happens;• When the UE is camped normally has found a better neighbouring cell than the cell on which it is

camping

• When the cell on which it is camping is no longer suitable

– The cells to camp on are ranked based on R criteria;

R (serving) = Qmeas(s) + qHyst(s)R (neighbour) = Qmeas(n) - qOffset(s,n)

qHyst1 CPICH RSCP qOffset1sn CPICH RSCPqHyst2 CPICH Ec/No qOffset2sn CPICH Ec/No

QMeas can be either RSCP or Ec/No depending on the value of parameter QualMeasQuantity. For GSM cells it always is RSCP. For WCDMA it is Ec/No by default

Cell Reselection WCDMA

Serving cell

Neighbour 1

Neighbour 2

QHyst1

Qoffset1sn

3

2

1

treSelection

Measurement Quantity

ranking ranking ranking

2

1

21

3

3

Camp on Neigbour1

Same idea as in GSM, serving cells are favored while neighbors are penalized

Measurements in Idle Mode

• UE starts Intra-frequency measurements if :Squal<=sIntraSearch [2 dB]

• UE starts Inter-Frequency measurements if :Squal<=sInterSearch [2 dB]

• UE starts GSM measurements if :Squal<=sRATSearch [2 dB]

And/or

Srxlev<=sHcsRat [2 dB]

Cell Reselection IRAT

treSelection (2 sec.)

IeF & IRAT Measurements in Cell_FACH mode

Measurements are controlled by 2 parameters in Cell_FACH mode;

interFreqFddMeasIndicator: TRUE or FALSE depending on presence of IeF neighborsTRUE UE will perform measurements and evaluate cell reselection criteria on IeF cellsFALSE UE will not perform measurements and will not evaluate cell reselection criteria on IeF cells

fachMeasOccaCycLenCoeff = 4 with this setting the UE will leave the FACH channel every 16th frame to perform measurements on IeF or IRAT neighbors(2fachMeasOccaCycLenCoeff = 24 = 16 (IeF or IRAT) or 23=8 (IeF and IRAT) )

Mobility Management Registrations

Location / Routing Area UpdateA new cell w/ different LAC/RAC

Periodic RegistrationLU is controlled by T3212 sent on BCCHRU is controlled by T3312 (CN parameter)

IMSI attach/detachDuring Switch on & off

Paging

UEs can be paged on;

•Idle Mode (Type I) via PICH & PCH [S-CCPCH]•Cell_FACH Mode (Type II) via DCH•Cell_DCH Mode (Type II) via DCH

Frame withPI Indicator

AssociatedS-CCPCH frame• • •

• • • • • •

• • •

PICH

S-CCPCH

PICH

PCH is only decoded when PICH indicates that there is a paging for UEs paging groupDRX (Discontinuous Reception) is used to limit battery consumption in idle mode

Idle Mode Paging

Master / System Information Blocks

Master Information

Block

System Information

Block 1

System Information

Block 3

System Information

Block n

The SIBs contain all information necessary for UEs to work properly in both Idle and Connected mode

Each SIB contains different kinds of information

Each SIB has its own repetition period (sibxRepPeriod)

The MIB has a fixed, predefined repetition rate equal to 80 ms

The UE reads the system information on the BCCH when the following events occur:

UE is powered up UE changes cell in Idle mode or in state CELL_FACH UE is informed of a change of System Information, when the UE is in Idle mode or state CELL_FACH UE moves from dedicated mode to common mode Timer expires for SIBs

Mapping of System Information onto MIB and SIBs

Contents MIB SIB1 SIB3 SIB5 SIB7 SIB11 SIB12

PLMN Identity xCell selection and

reselection parameters x x

Paging parameters xMeasurement management x x

Cell and common channel configuration x

Timers and counters in Idle mode x

Power Control on common channel x

Location and routing updating X

SIB Scheduling Information X