8.5.11 FACH measurement occasion calculation

25.3313GPPProtocol specificationRadio Resource Control (RRC)Release 17TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

For 3.84 Mcps TDD and 7.68 Mcps TDD, when in CELL_FACH state and when the variable C_RNTI is non-empty, or
for FDD and 1.28 Mcps TDD, when in CELL_FACH state, when the variable C_RNTI is non-empty and when variable HS_DSCH_RECEPTION_CELL_FACH_STATE is set to FALSE,
then the UE shall perform measurements as specified in subclauses 8.4.1.6 and 8.4.1.9 during the frame(s) with the SFN value fulfilling the following equation:

SFN div N = C_RNTI mod M_REP + n * M_REP

where

– N is the TTI (in number of 10ms frames) of the FACH having the largest TTI on the SCCPCH selected by the UE according to the procedure in subclause 8.5.19. FACHs that only carry MBMS logical channels (MTCH, MSCH, or MCCH) are excluded from measurement occasion calculations.

– C_RNTI is the C-RNTI value of the UE stored in the variable C_RNTI

– M_REP is the Measurement Occasion cycle length. According to the equation above, a FACH Measurement Occasion of N frames will be repeated every N * M_REP frame, and M_REP = 2^k.

where,

– k is the FACH Measurement occasion cycle length coefficient.
The value of the FACH Measurement occasion cycle length coefficient is read in system information in "System Information Block type 11" or "System Information Block type 12" in the IE "FACH measurement occasion info".

– n = 0,1,2… as long as SFN is below its maximum value

The UE is allowed to measure on other occasions in case the UE moves "out of service" area or in case it can simultaneously perform the ordered measurements.

A UE in TDD mode shall use the frame(s) with the SFN value fulfilling the above equation for neighbour cells measurements.

For FDD when in CELL_FACH state, when the variable C_RNTI is non-empty, when variable HS_DSCH_RECEPTION_CELL_FACH_STATE is set to TRUE, when variable COMMON_E_DCH_TRANSMISSION is set to FALSE, when the variable HS_DSCH_DRX_CELL_FACH_STATUS is set to FALSE, when the variable HS_DSCH_DRX_CELL_FACH_2CYCLE_STATUS is set to FALSE and when the variable HS_SCCH_DRX_CELL_FACH_STATUS is set to FALSE then the UE in FDD mode shall perform measurements as specified in subclauses 8.4.1.6 and 8.4.1.9 during the frame(s) with the SFN value fulfilling the following equation:

SFN = H-RNTI mod M_REP + n * M_REP

where

– H-RNTI is the value stored in the variable H_RNTI.

– M_REP is the Measurement Occasion cycle length. According to the equation above, a FACH Measurement Occasion of 10ms-frame will be repeated every M_REP frame, and M_REP = 2^k.

where,

– n = 0,1,2… as long as SFN is below its maximum value.

The UE is allowed to measure on other occasions in case the UE moves "out of service" area or in case it can simultaneously perform the ordered measurements.

NOTE: For FDD, in order to meet the MBMS demodulation performance requirements [21], a UE receiving MBMS PTM may not be able use the entire measurement occasion.

For 1.28 Mcps TDD when in CELL_FACH state, when the variable C_RNTI is non-empty, when variable HS_DSCH_RECEPTION_CELL_FACH_STATE is set to TRUE, and when the HS-SCCH(s), E-AGCH(s) and HS-PDSCH are not configured in TS0, then UE can perform the ordered measurements on any occasions.

For 1.28 Mcps TDD when in CELL_FACH state, when the variable C_RNTI is non-empty, when variable HS_DSCH_RECEPTION_CELL_FACH_STATE is set to TRUE, and when the HS-SCCH(s), E-AGCH(s) or HS-PDSCH are configured in TS0, then the UE shall perform measurements as specified in subclauses 8.4.1.6 and 8.4.1.9 during the frame(s) with the SFN value fulfilling the following equation:

SFN = H-RNTI mod M_REP + n * M_REP

where

– H-RNTI is the value stored in the variable H_RNTI.

– M_REP is the Measurement Occasion cycle length. According to the equation above, a FACH Measurement Occasion of 10ms-frame will be repeated every M_REP frame, and M_REP = 2^k.

where,

– n = 0,1,2… as long as SFN is below its maximum value.

The UE is allowed to measure on other occasions in case the UE moves "out of service" area or in case it can simultaneously perform the ordered measurements.