FeatureCombinationPreambles (FeatureCombinationPreambles-r17)
FeatureCombinationPreambles-r17 is an RRC information element of 3GPP TS 38.331 (38331), the 5G NR Radio Resource Control (RRC) protocol.
Definition
The IE FeatureCombinationPreambles associates a set of preambles with a feature combination. For parameters which can be provided in this IE, the UE applies this field value when performing Random Access using a preamble in this featureCombinationPreambles, otherwise the UE applies the corresponding value as determined by applicable Need Code, e.g. Need S. On a specific BWP, there can be at most one set of preambles associated with a given feature combination per RA Type (i.e. 4-step RACH or 2-step RACH) per MSG1 repetition number.
FeatureCombinationPreambles-r17 ::= SEQUENCE {
featureCombination-r17 FeatureCombination-r17,
startPreambleForThisPartition-r17 INTEGER (0..63),
numberOfPreamblesPerSSB-ForThisPartition-r17 INTEGER (1..64),
ssb-SharedRO-MaskIndex-r17 INTEGER (1..15) OPTIONAL, -- Need S
groupBconfigured-r17 SEQUENCE {
ra-SizeGroupA-r17 ENUMERATED {b56, b144, b208, b256, b282, b480, b640,
b800, b1000, b72, spare6, spare5,spare4, spare3, spare2, spare1},
messagePowerOffsetGroupB-r17 ENUMERATED { minusinfinity, dB0, dB5, dB8, dB10, dB12, dB15, dB18},
numberOfRA-PreamblesGroupA-r17 INTEGER (1..64)
} OPTIONAL, -- Need R
separateMsgA-PUSCH-Config-r17 MsgA-PUSCH-Config-r16 OPTIONAL, -- Cond MsgAConfigCommon
msgA-RSRP-Threshold-r17 RSRP-Range OPTIONAL, -- Need R
rsrp-ThresholdSSB-r17 RSRP-Range OPTIONAL, -- Need R
deltaPreamble-r17 INTEGER (-1..6) OPTIONAL, -- Need R
...,
[[
msg1-RepetitionNum-r18 ENUMERATED {n2, n4, n8, spare1} OPTIONAL, -- Cond Msg1Rep2
msg1-RepetitionTimeOffsetROGroup-r18 ENUMERATED {n4, n8, n16, spare1} OPTIONAL -- Cond Msg1Rep3
]]
}Candidate change requests of v18.1.0
The CRs whose title or cover names this change, strong and likely matches only.
- CR 4516 r1 (strong): Miscellaneous corrections to CE in RRC
Fields (14)
| Field | Description |
|---|---|
| featureCombination-r17 FeatureCombination-r17 | Indicates which combination of features that the preambles indicated by this IE are associated with. Network ensures that at least one field within the featureCombination is configured. The UE ignores a RACH resource defined by this FeatureCombinationPreambles if any feature within the featureCombination is not supported by the UE or if any of the spare fields within the featureCombination is set to true . |
| startPreambleForThisPartition-r17 INTEGER (0..63) | It defines the first preamble associated with the Feature Combination. If the UE is provided with a number N of SSB block indexes associated with one PRACH occasion, and N<1, the first preamble in each PRACH occasion is the one having the same index as indicated by this field. If N>=1, N blocks of preambles associated with the Feature Combination are defined, each having start index  + startPreambleForThisPartition , where n refers to SSB block index (see TS 38.213 [13], clause 8.1). |
| numberOfPreamblesPerSSB-ForThisPartition-r17 INTEGER (1..64) since v17.1.0 | It determines how many consecutive preambles are associated to the Feature Combination starting from the starting preamble(s) per SSB. |
| ssb-SharedRO-MaskIndex-r17 INTEGER (1..15) · OPTIONAL Need S | Mask index (see TS 38.321 [3]). Indicates a subset of ROs where preambles are allocated for this feature combination. If this field is configured within FeatureCombinationPreambles which is included in RACH-ConfigCommonTwoStepRA : - in case of separate ROs are configured for 4-step and 2-step random access, this field indicates a subset of ROs configured within this RACH-ConfigCommonTwoStepRA ; - in case shared ROs are used for 4-step and 2-step random access, it indicates the subset of ROs configured within RACH-ConfigCommon , which are the subset of ROs configured for 2-step random access. This field is configured when there is more than one RO per SSB. If the field is absent, all ROs configured in RACH-ConfigCommon or RACH-ConfigCommonTwoStepRA containing this FeatureCombinationPreambles are shared. The network does not configure this field, if the field msg1-RepetitionNum is configured. |
| groupBconfigured-r17 SEQUENCE { · OPTIONAL Need R since v17.1.0 | |
| ra-SizeGroupA-r17 ENUMERATED {b56, b144, b208, b256, b282, b480, b640, b800, b1000, b72, spare6, spare5,spare4, spare3, spare2, spare1} since v17.1.0 | Transport Blocks size threshold in bits below which the UE shall use a contention-based RA preamble of group A. (see TS 38.321 [3], clause 5.1.2). If this feature combination preambles are associated to a RACH-ConfigCommon-twostepRA , this field correspond to ra-MsgA-SizeGroupA , otherwise it corresponds to ra-Msg3SizeGroupA . |
| messagePowerOffsetGroupB-r17 ENUMERATED { minusinfinity, dB0, dB5, dB8, dB10, dB12, dB15, dB18} since v17.2.0 | Threshold for preamble selection. Value is in dB. Value minusinfinity corresponds to –infinity. Value dB0 corresponds to 0 dB, dB5 corresponds to 5 dB and so on (see TS 38.321 [3], clause 5.1.2). |
| numberOfRA-PreamblesGroupA-r17 INTEGER (1..64) since v17.2.0 | It determines how many consecutive preambles per SSB are associated to Group A starting from the starting preamble(s). The remaining preambles associated to the Feature Combination are associated to Group B |
| separateMsgA-PUSCH-Config-r17 MsgA-PUSCH-Config-r16 · OPTIONAL Cond MsgAConfigCommon | If present, it specifies how the 2-step RACH preambles identified by this FeatureCombinationPreambles are mapped to a PUSCH slot separate from the one defined in MsgA-ConfigCommon-r16. If the field is absent, the UE should apply the corresponding parameter in the RACH-ConfigCommonTwoStepRA of the BWP which includes the FeatureCombinationPreambles IE . |
| msgA-RSRP-Threshold-r17 RSRP-Range · OPTIONAL Need R since v17.1.0 | The UE selects 2-step random access type to perform random access based on this threshold (see TS 38.321 [3], clause 5.1.1). This field is only present if both 2-step and 4-step RA type are configured for the concerned feature combination in the BWP. If configured, this parameter overrides msgA-RSRP-Threshold-r16 . If absent, the UE applies msgA-RSRP-Threshold-r16 , if configured |
| rsrp-ThresholdSSB-r17 RSRP-Range · OPTIONAL Need R since v17.1.0 | UE may select the SS block and corresponding PRACH resource for path-loss estimation and (re)transmission based on SS blocks that satisfy the threshold (see TS 38.213 [13]). If this parameter is included in FeatureCombinationPreambles which is included in RACH-ConfigCommonTwoStepRA , it corresponds to msgA-RSRP-ThresholdSSB , as defined in TS 38.321 [3]. If this parameter is included in FeatureCombinationPreambles which is included in RACH-ConfigCommon , it it corresponds to rsrp-ThresholdSSB , as defined in TS 38.321 [3]. If this parameter is not included in FeatureCombinationPreambles which is included in RACH-ConfigCommon , the UE applies rsrp-ThresholdSSB included in the RACH-ConfigCommon which includes this FeatureCombinationPreambles . If this parameter is not included in FeatureCombinationPreambles which is included in RACH-ConfigCommonTwoStepRA , the UE applies msgA-RSRP-ThresholdSSB included in the RACH-ConfigCommonTwoStepRA which includes this FeatureCombinationPreambles . |
| deltaPreamble-r17 INTEGER (-1..6) · OPTIONAL Need R since v17.1.0 | Power offset between msg3 or msgA-PUSCH and RACH preamble transmission. If configured, this parameter overrides msg3-DeltaPreamble or msgA-DeltaPreamble , Actual value = field value 2 [dB] (see TS 38.213 [13], clause 7.1). If msgA-DeltaPreamble is configured in separateMsgA-PUSCH-Config-r17 , this field is absent. This field is set to the same value for all FeatureCombinationPreambles for MSG1 repetitions. |
| msg1-RepetitionNum-r18 ENUMERATED {n2, n4, n8, spare1} · OPTIONAL Cond Msg1Rep2 since v18.0.0 | Indicates which MSG1-repetition number that this FeatureCombinationPreambles is associated with. |
| msg1-RepetitionTimeOffsetROGroup-r18 ENUMERATED {n4, n8, n16, spare1} · OPTIONAL Cond Msg1Rep3 since v18.0.0 | Indicates a time offset of the starting ROs between two successive RO groups for a given repetition number (2, 4 or 8) associated with this FeatureCombinationPreambles for each frequency resource index within a time period (see TS 38.213 [13]). If this field is absent, the time offset is implicitly determined (see TS 38.213 [13]). For each MSG1 repetition number, the following values are applicable. • {n16}, for RO groups for MSG1 repetition number 8 • {n8, n16}, for RO groups for MSG1 repetition number 4 • {n4, n8, n16}, for RO groups for MSG1 repetition number 2 |