RACH-ConfigCommonTwoStepRA (RACH-ConfigCommonTwoStepRA-r16)
RACH-ConfigCommonTwoStepRA-r16 is an RRC information element of 3GPP TS 38.331 (38331), the 5G NR Radio Resource Control (RRC) protocol.
Definition
The IE RACH-ConfigCommonTwoStepRA is used to specify cell specific 2-step random-access type parameters.
RACH-ConfigCommonTwoStepRA-r16 ::= SEQUENCE {
rach-ConfigGenericTwoStepRA-r16 RACH-ConfigGenericTwoStepRA-r16,
msgA-TotalNumberOfRA-Preambles-r16 INTEGER (1..63) OPTIONAL, -- Need S
msgA-SSB-PerRACH-OccasionAndCB-PreamblesPerSSB-r16 CHOICE {
oneEighth ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64},
oneFourth ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64},
oneHalf ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64},
one ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64},
two ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32},
four INTEGER (1..16),
eight INTEGER (1..8),
sixteen INTEGER (1..4)
} OPTIONAL, -- Cond 2StepOnly
msgA-CB-PreamblesPerSSB-PerSharedRO-r16 INTEGER (1..60) OPTIONAL, -- Cond SharedRO
msgA-SSB-SharedRO-MaskIndex-r16 INTEGER (1..15) OPTIONAL, -- Need S
groupB-ConfiguredTwoStepRA-r16 GroupB-ConfiguredTwoStepRA-r16 OPTIONAL, -- Need S
msgA-PRACH-RootSequenceIndex-r16 CHOICE {
l839 INTEGER (0..837),
l139 INTEGER (0..137),
l571 INTEGER (0..569),
l1151 INTEGER (0..1149)
} OPTIONAL, -- Cond 2StepOnly
msgA-TransMax-r16 ENUMERATED {n1, n2, n4, n6, n8, n10, n20, n50, n100, n200} OPTIONAL, -- Need R
msgA-RSRP-Threshold-r16 RSRP-Range OPTIONAL, -- Cond 2Step4Step
msgA-RSRP-ThresholdSSB-r16 RSRP-Range OPTIONAL, -- Need R
msgA-SubcarrierSpacing-r16 SubcarrierSpacing OPTIONAL, -- Cond 2StepOnlyL139
msgA-RestrictedSetConfig-r16 ENUMERATED {unrestrictedSet, restrictedSetTypeA,
restrictedSetTypeB} OPTIONAL, -- Cond 2StepOnly
ra-PrioritizationForAccessIdentityTwoStep-r16 SEQUENCE {
ra-Prioritization-r16 RA-Prioritization,
ra-PrioritizationForAI-r16 BIT STRING (SIZE (2))
} OPTIONAL, -- Cond InitialBWP-Only
ra-ContentionResolutionTimer-r16 ENUMERATED {sf8, sf16, sf24, sf32, sf40, sf48, sf56, sf64} OPTIONAL, -- Cond 2StepOnly
...,
[[
ra-PrioritizationForSlicingTwoStep-r17 RA-PrioritizationForSlicing-r17 OPTIONAL, -- Cond InitialBWP-Only
featureCombinationPreamblesList-r17 SEQUENCE (SIZE(1..maxFeatureCombPreamblesPerRACHResource-r17)) OF FeatureCombinationPreambles-r17 OPTIONAL -- Cond AdditionalRACH
]]
}Fields (30)
| Field | Description |
|---|---|
| rach-ConfigGenericTwoStepRA-r16 RACH-ConfigGenericTwoStepRA-r16 | 2-step random access type parameters for both regular random access and beam failure recovery. |
| msgA-TotalNumberOfRA-Preambles-r16 INTEGER (1..63) · OPTIONAL Need S | Indicates the total number of preambles used for contention-based and contention-free 2-step random access type when ROs for 2-step are not shared with 4-step. If the field is absent, and 2-step and 4-step does not have shared ROs, all 64 preambles are available for 2-step random access type. |
| msgA-SSB-PerRACH-OccasionAndCB-PreamblesPerSSB-r16 CHOICE { · OPTIONAL Cond 2StepOnly | The meaning of this field is twofold: the CHOICE conveys the information about the number of SSBs per RACH occasion. Value oneEight corresponds to one SSB associated with 8 RACH occasions, value oneFourth corresponds to one SSB associated with 4 RACH occasions, and so on. The ENUMERATED part indicates the number of Contention Based preambles per SSB. Value n4 corresponds to 4 Contention Based preambles per SSB, value n8 corresponds to 8 Contention Based preambles per SSB, and so on. The total number of CB preambles in a RACH occasion is given by CB-preambles-per-SSB max(1, SSB-per-rach-occasion ). If the field is not configured in RACH-ConfigCommonTwoStepRA which is configured directly within a BWP (i.e. not within AdditionalRACH-Config ) and both 2-step and 4-step are configured for the BWP, the UE applies the value in the field ssb-perRACH-OccasionAndCB-PreamblesPerSSB in RACH-ConfigCommon. If the field is not configured in AdditionalRACH-Config and both 2-step and 4-step are configured in AdditionalRACH-Config , the UE applies the value in the field ssb-perRACH-OccasionAndCB-PreamblesPerSSB in RACH-ConfigCommon in the same AdditionalRACH-Config . The field is not present when RACH occasions are shared between 2-step and 4-step type random access in the BWP. |
| oneEighth ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64} | |
| oneFourth ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64} | |
| oneHalf ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64} | |
| one ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64} | |
| two ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32} | |
| four INTEGER (1..16) | |
| eight INTEGER (1..8) | |
| sixteen INTEGER (1..4) | |
| msgA-CB-PreamblesPerSSB-PerSharedRO-r16 INTEGER (1..60) · OPTIONAL Cond SharedRO | Number of contention-based preambles used for 2-step RA type from the non-CBRA 4-step type preambles associated with each SSB for RO shared with 4-step type RA. The number of preambles for 2-step RA type shall not exceed the number of preambles per SSB minus the number of contention-based preambles per SSB for 4-step type RA. The possible value range for this parameter needs to be aligned with value range for the configured SSBs per RACH occasion in ssb-perRACH-OccasionAndCB-PreamblesPerSSB in RACH-ConfigCommon . The field is only applicable for the case of shared ROs with 4-step type random access. |
| msgA-SSB-SharedRO-MaskIndex-r16 INTEGER (1..15) · OPTIONAL Need S | Indicates the subset of 4-step type ROs shared with 2-step random access type for each SSB. This field is configured when there is more than one RO per SSB. If the field is absent, and 4-step and 2-step has shared ROs, then all ROs are shared. |
| groupB-ConfiguredTwoStepRA-r16 GroupB-ConfiguredTwoStepRA-r16 · OPTIONAL Need S | Preamble grouping for 2-step random access type. If the field is absent then there is only one preamble group configured and only one msgA PUSCH configuration. |
| msgA-PRACH-RootSequenceIndex-r16 CHOICE { · OPTIONAL Cond 2StepOnly | PRACH root sequence index. If the field is not configured in RACH-ConfigCommonTwoStepRA which is configured directly within a BWP (i.e., not within AdditionalRACH-Config ), the UE applies the value in field prach-RootSequenceIndex in RACH-ConfigCommon in the configured BWP. If the field is absent in RACH-ConfigCommonTwoStepRA in AdditionalRACH-Config , the UE applies the corresponding value of prach-RootSequenceIndex in RACH-ConfigCommon in the same AdditionalRACH-Config . When both 2-step and 4-step type random access is configured, this field is only configured for the case of separate ROs between 2-step and 4-step type random access. For FR2-2, only the following values are applicable depending on the used subcarrier spacing: 120 kHz: L=139, L=571, and L=1151 480 kHz: L=139, and L=571 960 kHz: L=139 |
| l839 INTEGER (0..837) | |
| l139 INTEGER (0..137) | |
| l571 INTEGER (0..569) since v16.1.0 | |
| l1151 INTEGER (0..1149) since v16.1.0 | |
| msgA-TransMax-r16 ENUMERATED {n1, n2, n4, n6, n8, n10, n20, n50, n100, n200} · OPTIONAL Need R since v16.1.0 | Max number of MsgA preamble transmissions performed before switching to 4-step random access (see TS 38.321 [3], clauses 5.1.1). This field is only applicable when 2-step and 4-step RA type are configured and switching to 4-step type RA is supported. If the field is absent, switching from 2-step RA type to 4-step RA type is not allowed. |
| msgA-RSRP-Threshold-r16 RSRP-Range · OPTIONAL Cond 2Step4Step | 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 BWP. |
| msgA-RSRP-ThresholdSSB-r16 RSRP-Range · OPTIONAL Need R | 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]). |
| msgA-SubcarrierSpacing-r16 SubcarrierSpacing · OPTIONAL Cond 2StepOnlyL139 | Subcarrier spacing of PRACH (see TS 38.211 [16], clause 5.3.2). Only the following values are applicable depending on the used frequency: FR1/FR1-NTN: 15 or 30 kHz FR2-1/FR2-NTN: 60 or 120 kHz FR2-2: 120, 480, or 960 kHz. If the field is absent, the UE applies the SCS as derived from the msgA-PRACH-ConfigurationIndex in RACH-ConfigGenericTwoStepRA (see tables Table 6.3.3.1-1, Table 6.3.3.1-2, Table 6.3.3.2-2 and Table 6.3.3.2-3, TS 38.211 [16]) in case of 2-step only BWP, otherwise the UE applies the same SCS as Msg1 derived from RACH-ConfigCommon . The value also applies to contention free 2-step random access type ( RACH-ConfigDedicated ). |
| msgA-RestrictedSetConfig-r16 ENUMERATED {unrestrictedSet, restrictedSetTypeA, restrictedSetTypeB} · OPTIONAL Cond 2StepOnly | Configuration of an unrestricted set or one of two types of restricted sets for 2-step random access type preamble. If the field is not configured in RACH-ConfigCommonTwoStepRA which is configured directly within a BWP (i.e. not within AdditionalRACH-Config ), the UE applies the value in field restrictedSetConfig in RACH-ConfigCommon in the configured BWP. If the field is absent in RACH-ConfigCommonTwoStepRA in AdditionalRACH-Config , the UE applies the value of restrictedSetConfig in RACH-ConfigCommon in the same AdditionalRACH-Config . When both 2-step and 4-step type random access is configured, this field is only configured for the case of separate ROs between 2-step and 4-step type random access. |
| ra-PrioritizationForAccessIdentityTwoStep-r16 SEQUENCE { · OPTIONAL Cond InitialBWP-Only | |
| ra-Prioritization-r16 RA-Prioritization | Parameters which apply for prioritized random access procedure on any UL BWP of SpCell for specific Access Identities (see TS 38.321 [3], clause 5.1.1a). |
| ra-PrioritizationForAI-r16 BIT STRING (SIZE (2)) | Indicates whether the field ra-Prioritization-r16 applies for Access Identities. The first/leftmost bit corresponds to Access Identity 1, the next bit corresponds to Access Identity 2. Value 1 for an Access Identity indicates that the field ra-Prioritization-r16 applies, otherwise the field does not apply. |
| ra-ContentionResolutionTimer-r16 ENUMERATED {sf8, sf16, sf24, sf32, sf40, sf48, sf56, sf64} · OPTIONAL Cond 2StepOnly | The initial value for the contention resolution timer for fallback RAR in case no 4-step random access type is configured (see TS 38.321 [3], clause 5.1.5). Value sf8 corresponds to 8 subframes, value sf16 corresponds to 16 subframes, and so on. If both 2-step and 4-step random access type resources are configured on the BWP, then this field is absent. If the field is absent in RACH-ConfigCommonTwoStepRA in AdditionalRACH-Config , the UE shall apply the corresponding value in RACH-ConfigCommon in the same AdditionalRACH-Config. |
| ra-PrioritizationForSlicingTwoStep-r17 RA-PrioritizationForSlicing-r17 · OPTIONAL Cond InitialBWP-Only since v17.0.0 | Parameters which apply to configure prioritized CBRA 2-step random access type for slicing. |
| featureCombinationPreamblesList-r17 SEQUENCE (SIZE(1..maxFeatureCombPreamblesPerRACHResource-r17)) OF FeatureCombinationPreambles-r17 · OPTIONAL Cond AdditionalRACH since v17.1.0 | Specifies a series of preamble partitions each associated to a combination of features and 2-step RA. The network does not configure this list to have more than 16 entries. |
Used by (1)
Uses (8)
- FeatureCombinationPreambles-r17
- GroupB-ConfiguredTwoStepRA-r16
- RA-Prioritization
- RA-PrioritizationForSlicing-r17
- RACH-ConfigGenericTwoStepRA-r16
- RSRP-Range
- SubcarrierSpacing
- maxFeatureCombPreamblesPerRACHResource-r17