wcdma-idle-mode
Post on 19-Jan-2016
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DESCRIPTION
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Idle Mode
Content
Cell Selection
Cell Reselection
Parameter Configuration
Cell Selection
The UE will select an initial cell at power-on or do registration after ‘out of service’ conditions.
When the UE moves in the IDLE mode, in state URA_PCH or CELL_FACH, it needs to change the cell that it camps on through the cell reselection strategy.
Cell Selection for FDD cells: Srxlev > 0 AND Squal > 0
for TDD cells: Srxlev > 0
Squal = Qqualmeas – Qqualmin
Srxlev = Qrxlevmeas - Qrxlevmin - Pcompensation
Qqualmeas: The quality of received signal expressed in CPICH Ec/N0 (dB). Qrxlevmeas: Measured cell RX level value. This is received signal, CPICH RSCP for FDD
cells (dBm), P-CCPCH RSCP for TDD cells (dBm) and RXLEV for GSM cells (dBm). Qqualmin: Minimum required quality level in the cell (dB). Qrxlevmin: Minimum required RX level in the cell (dBm).
Pcompensation = max(UE_TXPWR_MAX_RACH – P_MAX, 0)
UE_TXPWR_MAX_RACH: Maximum TX power level MaxRACHTxPwr on RACH (read in system information) (dBm) (for cells under the RNC, it is the max value of MaxRACHTxPwr (Prach); for cells under other RNC, it is the value of MaxRACHTxPwr (externalUtranCell)).
P_MAX: Maximum RF output power of the UE (dBm)
Content
Cell Selection
Cell Reselection
Parameter Configuration
Cell Reselection
If the serving cell uses the HCS (UseOfHCS (utranCell)) structure, the following cell reselection rule H is used for quality ranking in cell reselection.
Hs = Qmeas,s - Qhcss
Hn = Qmeas,n - Qhcsn – TOn * Ln
TOn = TEMP_OFFSETn * W(PENALTY_TIMEn – Tn)
Ln = 0 if HCS_PRIOn = HCS_PRIOs
Ln = 1 if HCS_PRIOn <> HCS_PRIOs
W(x) = 0 for x < 0W(x) = 1 for x >= 0
Cell Reselection
If the cell does not use the HCS structure, the following cell reselection rule R is used for quality ranking in cell reselection.
Rs = Qmeas,s + Qhysts + Qoffmbms Rn = Qmeas,n - Qoffsets,n + Qoffmbms - TOn * (1 – Ln)
TOn = TEMP_OFFSETn * W(PENALTY_TIMEn – Tn)
Ln = 0 if HCS_PRIOn = HCS_PRIOs
Ln = 1 if HCS_PRIOn <> HCS_PRIOs
W(x) = 0 for x < 0W(x) = 1 for x >= 0
How the suitable cell is selected
If a TDD or GSM cell is ranked as the best cell, then the UE will perform cell re-selection to that TDD or GSM cell and camps on the chosen cell.
If an FDD cell is ranked as the best cell and the quality measurement for cell selection and re-selection is set to CPICH RSCP, the UE will perform cell re-selection to that FDD cell and and camps on the chosen cell
If an FDD cell is ranked as the best cell and the quality measure for cell selection and re-selection is set to CPICH Ec/No, the UE shall perform a second ranking of the FDD cells according to the R criteria specified above, but using the quality measure CPICH Ec/No for deriving the Qmeas,n and Qmeas,s and calculating the R values of the FDD cells
Content
Cell Selection
Cell Reselection
Parameter Configuration
Parameter Configuration
Parameter Configuration
Parameter Configuration
13
Intra-Frequency Cell Reselection
Time
P-CPICH Ec/No
Serving CellServing Cell
Neighboring Cell
Neighboring Cell
Neighboring cell criterion S
is fulfilled and is ranked
Neighboring cell better ranking
than Serving cell
UE perform cell reselection
Treselections
Qhyst2s
Qoffset2s,n
Qqualmin
UE perform intra-frequency measurements
Qqualmin + SIntraSearch
Intra-Frequency Cell Reselection Key Parameter ListParameter Explanation
QqualminThe parameter indicates the cell’s minimum required quality value which fulfills the cell selection suitability criterion. The measured cell whose CPICH Ec/No is lower than Qqualmin cannot be selected.
Qrxlevmin
The parameter indicates the cell’s minimum required Rx level value which fulfills the cell selection suitability criterion. The measured cell whose CPICH RSCP or Rx level is lower than Qrxlevmin cannot be selected.
SintrasearchThe parameter indicates the threshold to trigger the measurement for intra-frequency cell reselection.
Qhyst2sThe parameter indicates the hysteresis value for FDD cells when the measurement quantity for cell reselection is CPICH Ec/No.
Qoffset2s,nThe parameter indicates the offset between the serving cell and
neighbor cell when measurement quantity is CPICH Ec/No.
Treselection This parameter indicates the cell reselection timer value.
Inter-RAT Cell Reselection Sample
Time
Quality/RxLev
GSM Serving Cell
WCDMA Serving Cell
GSM Neighboring Cell WCDMA
Neighboring Cell
Inter-RAT cell criterion S is fulfilled and is
ranked
Neighbor cell is better ranking
than Serving cell
UE performs inter-RAT cell
reselection
Treselections
Qhyst1s
Qoffset1s,n
Qrxlevmin(GSM)
UE performs inter-RAT
measurements
Qqualmin + SSearchRat
3G→2G Cell Reselection Key Parameter List
Parameter Explanation
QqualminThe parameter indicates the cell’s minimum required quality value which fulfills the cell selection suitability criterion. The measured cell whose CPICH Ec/No is lower than Qqualmin cannot be selected.
QrxlevminThe parameter indicates the cell’s minimum required Rx level value which fulfills the cell selection suitability criterion. The measured cell whose CPICH RSCP or Rx level is lower than Qrxlevmin cannot be selected.
SSearchRatThe parameter indicates the threshold to trigger the measurement for inter-RAT cell reselection.
Qhyst1sThe parameter indicates the hysteresis value for FDD cells when the measurement quantity for cell reselection is CPICH RSCP.
Qoffset1s,nThe parameter indicates the offset between the serving cell and neighbor cell when measurement quantity is CPICH RSCP.
Treselection This parameter indicates the cell reselection timer value.
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