2G-3G Idle Reselection

1. 3G To 2G Reselection.

No Event

1 Inter-RAT Measurement triggering(GSM Cell Measuring Starting)

Squal>SsearchRAT

Squal = CPICH_EcNo measure – Qqualmin

CPICH_EcNo is the measured value of pilot in the serving cell.

SsearchRAT and Qqualmin are parameters in system information.

2 Evaluation GSM cell along with WCDMA cells

UE selects cells that accord with an "S rule"

"S Rule"

for FDD cells: Srxlev > 0 AND Squal > 0

Squal = Qqualmeas – Qqualmin

for TDD cells: Srxlev > 0

Srxlev = Qrxlevmeas - Qrxlevmin - Pcompensation

2. 2G To 3G Reseltion.

No. Event

1 Inter-RAT measurement trigering(Starting to measure WCDMA Cells)

Qsearch_I Threshold determine the triggering

Qsearch_I means the idle state of CS domain, Ericsson : QSI used for Idle & Packet Mode

Qsearch_C_Initial means building the connection phase of CS domain Ericsson : QSC for active mode

Qsearch_P means GPRS domain

2 Algoritham for reselecting 2G to WCDMA

after triggering UE update RLA_C & 6 strong WCDMA Cells level

RLA_C : Average Rx Level of serving cell & Neighbor Cells

[CPICH Ec/No > FDDqmin] & [CPICH RSCP > RLA_C + FDDqoff]

FDDqmin : Minimum Ec/No level for reselect

FDDqoff : Offset between GSM & WCDMA rx level for reselect

Important;

After selecting UTRAN cell FDDqoff value increase by 5db for 15s period

UE can not reselect UTRAN cell until 5 seconds if UE reselects a proper GSM cell