8.4a Measurements in CELL_FACH State when HS-DSCH discontinuous reception is ongoing

25.1333GPPRelease 17Requirements for support of radio resource management (FDD)TS

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

8.4a.1 Introduction

This section contains requirements on the UE regarding cell reselection and measurement reporting in CELL_FACH state when HS-DSCH discontinuous reception is ongoing. The requirements for cell re-selection are split in FDD intra frequency, FDD inter frequency, TDD, GSM and E-UTRA measurements. The measurements are defined in TS 25.215, the measurement model is defined in TS 25.302 and measurement accuracies are specified in section 9. Control of measurement reporting is specified in TS 25.331. DRX in CELL_FACH state is described in TS 25.331.

If UE indicates support for increased UE carrier monitoring UTRA or increased carrier monitoring E-UTRA the measurement performance for different carriers may be configured by higher layers to be either normal or reduced. A measurement scaling factor [16] defining the relaxation to be applied to the requirements for carriers measured with reduced measurement performance is signalled by higher layers and has the possible settings shown in table 8.0a. The same measurement scaling factor mapping is used in Cell FACH state as cell DCH state.

The minimum performance requirements for a UE which indicates support for Increased UE carrier monitoring UTRA [16, 31] are calculated as defined in section 8.4a.2.3 provided that N_{freq, FDD,n} ≤2 or if all FDD interfrequency carriers are indicated to have normal performance. The minimum performance requirements for a UE which indicates support for Increased UE carrier monitoring E-UTRA [16, 31] are calculated as defined in section 8.4a.2.6 provided that N_E-UTRA,n≤4 for a UE capable of either FDD E-UTRA carrier monitoring or TDD E-UTRA carrier monitoring or N_{freq,E-UTRA,n}≤8 for a UE capable of both FDD and TDD E-UTRA carrier monitoring provided N_{freq,E-UTRA,n,FDD}≤4 and N_{freq,E-UTRA,n,TDD}≤4 or if all E-UTRA carriers are indicated to have normal performance.

Capabilities for number of carriers to monitor for UE which indicates support for Increased UE carrier monitoring UTRA or E-UTRA are specified in section 8.4.2.1a.

8.4a.2 Requirements

8.4a.2.1 UE Measurement Capability

In CELL_FACH state, the number of cells the UE shall be able to monitor is defined in section 8.4.2.1 and 8.4.2.1a.

The requirements in section 9 on CPICH Ec/Io and RSCP measurements are applicable for a UE performing measurements according to this section. For inter-frequency FDD, TDD, GSM and E-UTRAN cell re-selection, DRX gaps as specified in TS 25.331 are used to find and measure on other cells.

It is defined below how the measurements on different systems and modes are performed given the time allocated to that system. The requirements in this section are based on an assumption that the time during the DRX gaps that is allocated to each of the different modes and systems shall be equally shared by the modes which the UE has capability for and that are in the monitored set signalled by the network.

8.4a.2.2 FDD intra frequency measurements when HS-DSCH discontinuous reception is ongoing

During the CELL_FACH state the UE shall continuously measure identified intra frequency cells and search for new intra frequency cells in the monitoring set during the on part of the DRX cycle.

8.4a.2.2.1 Identification of a new cell

The UE shall be able to identify a new detectable cell belonging to the monitored set within

where

is 300ms

HS-DSCH Rx burst_FACH is the duration of the on part of the DRX cycle (frames)

HS-DSCH DRX cycle_FACH is the duration of the total DRX cycle (frames)

A cell shall be considered detectable when

– CPICH Ec/Io > -17 dB,

– SCH_Ec/Io > -17 dB for at least one channel tap and SCH_Ec/Ior is equally divided between primary synchronisation code and secondary synchronisation code.

8.4a.2.2.2 UE CPICH measurement capability

In the CELL_FACH state the measurement period for intra frequency measurements is

The UE shall be capable of performing CPICH measurements for 8 identified intra-frequency cells of the monitored set and the UE physical layer shall be capable of reporting measurements to higher layers with the measurement period of T_{Measurent_Period,Intra}.

where

HS-DSCH Rx burst_FACH is the duration of the on part of the DRX cycle (frames)

HS-DSCH DRX cycle_FACH is the duration of the total DRX cycle (frames)

8.4a.2.2.3 RACH reporting

Reporting measurements in the measurement reports sent on the RACH shall meet the requirements in section 9.

8.4a.2.3 FDD inter frequency measurements

In the CELL_FACH state when DRX is being performed by the UE, the UE shall measure identified inter frequency cells and search for new inter frequency cells indicated in the measurement control information, according to the measurement rules defined in [1].

When absolute priority based reselection is used:

– If Srxlev_ServingCell > S_{prioritysearch1} and Squal_ServingCell > S_{prioritysearch2} then the UE shall search for inter frequency layers of higher priority at least every T_{higher_priority_search},where T_{higher_priority_search} is described in section 4.2.2.

– If Srxlev_ServingCell <= S_{prioritysearch1} or Squal_ServingCell <= S_{prioritysearch2} then the UE shall search for all inter frequency layers based on the requirements below.

If E-DCH resources are allocated to the UE or timer T321 [16] is running, the UE is not required to perform interfrequency cell identification or measurements as continuous HS-DSCH reception is required.

8.4a.2.3.1 Identification of a new cell

The UE shall be able to identify a new detectable cell belonging to the monitored set within

(normal performance) and

(reduced performance)

where

T_{basic_identify_FDD,inter} is specified in 8.1.2.3.2.

N_Freq,FDD: Number of FDD frequencies in the Inter-frequency cell info list

N_Freq,FDD,n: Number of frequencies in the inter frequency cell info list indicated for normal performance

N_Freq,FDD,r: Number of frequencies in the inter frequency cell info list indicated for reduced performance excluding any interfrequency higher priority layers indicated to have reduced performance

If N_Freq,FDD,r is not equal to zero then K_n and K_r are as shown in table 8.0a. Otherwise K_n=1 and all interfrequency layers have normal performance.

The minimum performance requirements for a UE which does not indicate support for Increased UE carrier monitoring UTRA [16,31] are calculated assuming all UTRA carriers required to be monitored for such UE, are having normal performance and are in normal performance group, i.e. N_Freq,FDD,n = N_Freq,FDD and N_Freq,FDD,r=0.

T_{Inter FACH,DRX} = Min(HS-DSCH DRX cycle_FACH – HS-DSCH Rx burst_FACH, HS-DSCH Rx burst_FACH)- 2*0.5ms [ms]

HS-DSCH Rx burst_FACH is the duration of the on part of the DRX cycle (frames)

HS-DSCH DRX cycle_FACH is the duration of the total DRX cycle (frames)

T_scale = N_FDD+ N_TDD + N_GSM + N_E-UTRAN

If absolute priority based reselection is used, and Srxlev_ServingCell > S_{prioritysearch1} and Squal_ServingCell > S_{prioritysearch2}, T_{identify, inter} shall be increased by T_{higher_priority_search.}

A cell shall be considered detectable when

– CPICH Ec/Io > -17 dB,

– SCH_Ec/Io > -17 dB for at least one channel tap and SCH_Ec/Ior is equally divided between primary synchronisation code and secondary synchronisation code.

8.4a.2.3.2 UE CPICH measurement capability

The UE physical layer shall be capable of reporting measurements to higher layers with measurement accuracy as specified in sub-clause 9.1.2 with measurement period is given by within

ms (normal performance) and

ms ( reduced performance)

where

N_Freq,FDD: Number of FDD frequencies in the Inter-frequency cell info list

N_Freq,FDD,n: Number of frequencies in the inter frequency cell info list indicated for normal performance

N_Freq,FDD,r: Number of frequencies in the inter frequency cell info list indicated for reduced performance excluding any interfrequency higher priority layers indicated to have reduced performance

If N_Freq,FDD,r is not equal to zero then K_n and K_r are as shown in table 8.0a. Otherwise K_n=1 and all interfrequency layers have normal performance.

T_{Measurement_Period Inter} is specified in section 8.1.2.3.2.

T_{Inter FACH,DRX} = Min(HS-DSCH DRX cycle_FACH – HS-DSCH Rx burst_FACH, HS-DSCH Rx burst_FACH)- 2*0.5ms [ms]

HS-DSCH Rx burst_FACH is the duration of the on part of the DRX cycle (frames)

HS-DSCH DRX cycle_FACH is the duration of the total DRX cycle (frames)

The UE shall be capable of performing CPICH measurements for X_{basic measurement FDD inter}inter-frequency cells per FDD frequency of the monitored set, and the UE physical layer shall be capable of reporting measurements to higher layers with the measurement period of T_{Measurement_ Inter.}

X_{basic measurement FDDinter}is defined in section 8.1.2.3.2

T_scale = N_FDD+ N_TDD + N_GSM + N_E-UTRAN

8.4a.2.4 TDD measurements when HS-DSCH discontinuous reception is ongoing

The requirements in this section shall apply to UE supporting FDD and TDD.

The UE shall continuously measure identified inter frequency TDD cells and search for new inter-frequency TDD cells indicated in the measurement control information. If E-DCH resources are allocated to the UE or timer T321[16] is running, the UE is not required to perform interfrequency TDD cell identification or measurements as continuous HS-DSCH reception is required.

8.4a.2.4.1 Identification of a new cell

8.4.2.4.1.1 3,84 Mcps TDD Option

The UE shall be able to identify a new detectable inter-frequency TDD cell belonging to the monitored set within

Where

T_{basic_identify_TDD,inter} = 800ms

N_Freq,TDD: Number of TDD frequencies indicated in the Inter-frequency cell info list

T_{Inter FACH,DRX} = Min(HS-DSCH DRX cycle_FACH – HS-DSCH Rx burst_FACH, HS-DSCH Rx burst_FACH _n)- 2*0.5ms [ms]

HS-DSCH Rx burst_FACH is the duration of the on part of the DRX cycle (frames)

HS-DSCH DRX cycle_FACH is the duration of the total DRX cycle (frames)

T_scale = N_FDD+ N_TDD + N_GSM

When L3 filtering is used an additional delay can be expected.

An inter-frequency TDD cell shall be considered detectable when P-CCPCH_Ec/Io ≥ -8 dB and SCH_Ec/Io ≥ -13 dB.

The received P-CCPCH_E_c/I_o is defined as

and the received SCH_E_c/I_o is defined as

8.4a.2.4.1.2 1.28 Mcps TDD Option

The UE shall be able to identify a new detectable inter-frequency TDD cell belonging to the monitored set within

where

T_{basic_identify_TDD,inter} = 800ms

N_Freq,TDD: Number of TDD frequencies indicated in the Inter-frequency cell info list

T_{Measurement_Period TDD inter}is specified in section 8.1.2.4.2

T_{Inter FACH,DRX} = Min(HS-DSCH DRX cycle_FACH – HS-DSCH Rx burst_FACH, HS-DSCH Rx burst_FACH)- 2*0.5ms [ms]

HS-DSCH Rx burst_FACH is the duration of the on part of the DRX cycle (frames)

HS-DSCH DRX cycle_FACH is the duration of the total DRX cycle (frames)

T_scale = N_FDD+ N_TDD + N_GSM

When L3 filtering is used an additional delay can be expected.

A cell shall be considered detectable when P-CCPCH Ec/Io > -8 dB and DwPCH_Ec/Io > -5 dB.

The received P-CCPCH E_c/I_o is defined as

The received DwPTS E_c/I_o is defined as

8.4a.2.4.2 P-CCPCH RSCP measurement period

When a DRX cycle as previously described is scheduled for inter frequency TDD measurements the UE physical layer shall be capable of reporting measurements to higher layers with measurement accuracy as specified in sub-clause 9.1.11 and with a measurement period as given by

where

N_Freq,TDD: Number of TDD frequencies in the Inter-frequency cell info list

T_{Measurement_Period Inter} is specified in section 8.1.2.3.2.

T_{Inter FACH,DRX} = Min(HS-DSCH DRX cycle_FACH – HS-DSCH Rx burst_FACH, HS-DSCH Rx burst_FACH)- 2*0.5ms [ms]

HS-DSCH Rx burst_FACH is the duration of the on part of the DRX cycle (frames)

HS-DSCH DRX cycle_FACH is the duration of the total DRX cycle (frames)

T_scale = N_FDD+ N_TDD + N_GSM

The UE shall be capable of performing P-CCPCH RSCP measurements for X_{basic measurement TDD inter}inter-frequency TDD cells per TDD frequency of the monitored set and the UE physical layer shall be capable of reporting measurements to higher layers with the measurement period of T_{Measurement TDD}.

X_{basic measurement TDD inter}is defined in section 8.1.2.4.2

8.4a.2.5 GSM measurements when HS-DSCH discontinuous reception is ongoing

The requirements in this section apply only to UE supporting FDD and GSM. If E-DCH resources are allocated to the UE or timer T321[16] is running, the UE is not required to perform GSM BSIC identification or RSSI measurement.

To support cell reselection the UE shall always perform BSIC verification in Cell FACH state.

8.4a.2.5.1 GSM carrier RSSI

A UE supporting GSM measurements shall be able to measure at least 32 GSM cells and shall be able to obtain RSSI samples of these cells during a DRX off period. In the CELL_FACH state the measurement period for the GSM carrier RSSI measurement is

T_{measurement_period,GSM}=min(30720,max(480ms,T_scale*T_DRX__CYCLE*6)).

The UE shall meet the measurement accuracy requirements stated for RXLEV in TS 45.008, when the given measurement time allows the UE to take at least 3 GSM carrier RSSI samples per GSM carrier in the monitored set during the measurement period.

In case UTRA RACH procedure prevents the UE from acquiring the required number of samples per GSM carrier during one measurement period, the GSM carriers that were not measured during that measurement period shall be measured in the following measurement periods.

8.4a.2.5.2 BSIC verification

The procedure for BSIC verification on a GSM cell can be divided into the following two tasks:

Initial BSIC identification
Includes searching for the BSIC and decoding the BSIC for the first time when there is no knowledge about the relative timing between the FDD and GSM cell. The requirements for Initial BSIC identification can be found in 8.4a.2.5.2.1.

BSIC re-confirmation
Tracking and decoding the BSIC of a GSM cell after initial BSIC identification is performed. The requirements for BSIC re-confirmation can be found in 8.4s.2.5.2.2.

The BSIC of a GSM cell is considered to be "verified" if the UE has decoded the SCH of the BCCH carrier and identified the BSIC at least one time (initial BSIC identification) and from that moment the BSIC shall be re-confirmed at least once every 30 seconds. Otherwise the BSIC of the GSM cell is considered as "non-verified".

The UE shall be able to decode a BSIC within a measurement occasion when the time difference between the middle of the received GSM synchronisation burst at the UE and the middle of the measurement occasion is within TBD.

The UE shall be able to perform BSIC verification at levels down to the reference sensitivity level or reference interference levels as specified in TS 45.005.

8.4a.2.5.2.1 Initial BSIC identification

The UE shall continuously attempt to decode the BSIC of SCH on the BCCH carrier of the 6 strongest BCCH carriers of the GSM cells indicated in the Inter-RAT cell info list. The UE shall give priority for BSIC decoding attempts in decreasing signal strength order to BCCH carriers with unknown BSIC. The strongest BCCH carrier is defined as the BCCH carrier having the highest measured GSM carrier RSSI value.

If the BSIC of the GSM BCCH carrier has been successfully decoded the UE shall immediately continue BSIC identification with the next GSM BCCH carrier, in signal strength order, with unknown BSIC. The GSM cell for which the BSIC has been successfully identified shall be moved to the BSIC re-confirmation procedure.

The UE is required to decode the BSIC within T_{identify_GSM,DRX} =500ms for all DRX cycles. This value guarantees at least two attempts to decode the BSIC for one GSM BCCH carrier.

If the UE has not successfully decoded the BSIC of the GSM BCCH carrier within T_{identify_GSM,DRX} =500 ms, the UE shall abort the BSIC identification attempts for that GSM BCCH carrier. The UE shall continue to try to perform BSIC identification of the next GSM BCCH carrier in signal strength order. The GSM BCCH carrier for which the BSIC identification failed shall not be re-considered for BSIC identification until BSIC identification attempts have been made for all the rest of the 6 strongest GSM BCCH carriers in the monitored set with unknown BSIC. Additionally, the UE is not required to attempt to decode the BSIC of a GSM carrier for a period of 30 seconds after an unsuccessful decoding attempt has been made on that GSM carrier.

8.4a.2.5.2.2 BSIC re-confirmation

The requirements of this section are applicable for BSIC re-confirmation.

The UE shall maintain the timing information of 6 identified GSM cells. Initial timing information is obtained from the initial BSIC identification. The timing information shall be updated every time the BSIC is decoded.

If the UE fails to decode the BSIC after two successive attempts the UE shall abort the BSIC re-confirmation attempts for that GSM cell. The GSM cell shall be treated as a new GSM cell with unidentified BSIC and the GSM cell shall be moved to the initial BSIC identification procedure, see section 8.4a.2.5.2.1. The UE shall be able to make BSIC re-confirmation attempts for the 6 strongest GSM cells in the monitored list.

The UE shall perform BSIC re-confirmation at least every T_{re-confirm_GSM,DRX} =30 seconds.

8.4a.2.6 E-UTRA measurements when HS-DSCH discontinuous reception is ongoing

In the CELL_FACH state when DRX is being performed by the UE, the UE shall measure identified E-UTRAN cells and search for new E-UTRAN cells indicated in the measurement control information, according to the measurement rules defined in [1].

When absolute priority based reselection is used:

– If Srxlev_ServingCell > S_{prioritysearch1} and Squal_ServingCell > S_{prioritysearch2} then the UE shall search for E-UTRA layers of higher priority at least every T_{higher_priority_search}where T_{higher_priority_search} is described in section 4.2.2.

– If Srxlev_ServingCell <= S_{prioritysearch1} or Squal_ServingCell <= S_{prioritysearch2} then the UE shall search for all E-UTRA layers based on the requirements below.

If E-DCH resources are allocated to the UE or timer T321 [16] is running, the UE is not required to perform E-UTRAN cell identification or measurements as continuous HS-DSCH reception is required.

The requirements below apply to both cell reselection to E-UTRA and network controlled mobility to E-UTRA (i.e. E-UTRA measurement for CELL_FACH and E-UTRA RACH reporting).

8.4a.2.6.1 Identification of a new cell

The UE shall be able to identify a new detectable cell belonging to the monitored set within

(normal performance) and

(reduced performance)

where

T_{basic_identify_E-UTRAN}is specified in 8.1.2.6.

N_E-UTRA: Number of E-UTRA frequencies in the E-UTRA neighbor list

N_E-UTRA,n: Number of frequencies in the E-UTRA neighbour list indicated for normal performance

N_E-UTRA,r: Number of frequencies in the E-UTRA neighbour list indicated for reduced performance excluding any E-UTRA higher priority layers indicated to have reduced performance.

If N_E-UTRA,r is not equal to zero then K_n and K_r are as shown in table 8.0a. Otherwise K_n=1 and all E-UTRA layers have normal performance.

The minimum performance requirements for a UE which does not indicate support for Increased UE carrier monitoring E-UTRA [16,31] are calculated assuming all E-UTRA carriers required to be monitored for such UE, are having normal performance and are in normal performance group, i.e. N_{E-UTRA, n} = N_E-UTRA and N_{E-UTRA, r}=0.

T_{E-UTRAN FACH,DRX} = Min(HS-DSCH DRX cycle_FACH – HS-DSCH Rx burst_FACH, HS-DSCH Rx burst_FACH)- 2*0.5ms [ms]

HS-DSCH Rx burst_FACH is the duration of the on part of the DRX cycle (frames)

HS-DSCH DRX cycle_FACH is the duration of the total DRX cycle (frames)

T_scale = N_FDD+ N_TDD + N_GSM + N_E-UTRAN

If absolute priority based reselection is used, and Srxlev_ServingCell > S_{prioritysearch1} and Squal_ServingCell > S_{prioritysearch2}, T_{identify, E-UTRAN} shall be increased by T_{higher_priority_search.}

A cell shall be considered detectable according to [36.133]

8.4a.2.6.2 UE RSRP and RSRQ measurement capability

The UE physical layer shall be capable of reporting E-UTRA measurements to higher layers with measurement accuracy as specified in sub-clause 9.1.4a/b with measurement period given by

ms (normal peformance) and

ms (reduced performance)

where

N_E-UTRA: Number of E-UTRA frequencies in the E-UTRA cell info list

N_E-UTRA,n: Number of frequencies in the E-UTRA neighbour list indicated for normal performance

N_E-UTRA,r: Number of frequencies in the E-UTRA neighbour list indicated for reduced performance excluding any E-UTRA higher priority layers indicated to have reduced performance.

If N_E-UTRA,r is not equal to zero then K_n and K_r are as shown in table 8.0a. Otherwise K_n=1 and all E-UTRA layers have normal performance.

T_{Measurement_Period E-UTRAN} is specified in section 8.1.2.6.

T_{basic_measurement_E-UTRAN} = 60 ms.

T_{E-UTRAN FACH,DRX} = Min(HS-DSCH DRX cycle_FACH – HS-DSCH Rx burst_FACH, HS-DSCH Rx burst_FACH)- 2*0.5ms [ms]

HS-DSCH Rx burst_FACH is the duration of the on part of the DRX cycle (frames)

HS-DSCH DRX cycle_FACH is the duration of the total DRX cycle (frames)

T_scale = N_FDD+ N_TDD + N_GSM + N_E-UTRA

8.4a.2.6.3 E-UTRA measurements reporting

If E-UTRA measurement for CELL_FACH is configured by upper layers, UE can report measurements in measurement reports, whose report criteria can be set to Event triggered or Periodical reporting. In both cases, the UE shall send only one measurement report. The UE shall be able to support at least 1 E-UTRA measurement per carrier on up to 4 E-UTRA carriers for CELL_FACH configuration.

Reported measurements shall meet the requirements in section 9.

8.4a.2.6.3.1 Event Triggered reporting

The measurement reporting delay is defined as the time between the triggering of a measurement report (the measured quality of any cell on a configured E-UTRA frequency exceeds the configured threshold) until the moment in time when the UE starts sending the preambles on the PRACH for sending the measurement report

The event triggered measurement reporting delay shall be less than T _{identify ,E-UTRAN} + T_RA, where T _{identify ,E-UTRAN} is defined in Section 8.4.2.6.1 and T_RA is the additional delay caused by the random access procedure.

If a cell has been detectable at least for the time period than T _{identify ,E-UTRAN} and then triggers the measurement report, the event triggered measurement reporting delay shall be less than T_{Measurement_Period_E-UTRAN} + T_RA provided the timing to that cell has not changed more than ± 50 Ts while transmission gap has not been available.