RACH-ConfigCommon
RACH-ConfigCommon is an RRC information element of 3GPP TS 38.331 (38331), the 5G NR Radio Resource Control (RRC) protocol.
Definition
The IE RACH-ConfigCommon is used to specify the cell specific random-access parameters.
RACH-ConfigCommon ::= SEQUENCE {
rach-ConfigGeneric RACH-ConfigGeneric,
totalNumberOfRA-Preambles INTEGER (1..63) OPTIONAL, -- Need S
ssb-perRACH-OccasionAndCB-PreamblesPerSSB 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, -- Need M
groupBconfigured SEQUENCE {
ra-Msg3SizeGroupA ENUMERATED {b56, b144, b208, b256, b282, b480, b640,
b800, b1000, b72, spare6, spare5,spare4, spare3, spare2, spare1},
messagePowerOffsetGroupB ENUMERATED { minusinfinity, dB0, dB5, dB8, dB10, dB12, dB15, dB18},
numberOfRA-PreamblesGroupA INTEGER (1..64)
} OPTIONAL, -- Need R
ra-ContentionResolutionTimer ENUMERATED { sf8, sf16, sf24, sf32, sf40, sf48, sf56, sf64},
rsrp-ThresholdSSB RSRP-Range OPTIONAL, -- Need R
rsrp-ThresholdSSB-SUL RSRP-Range OPTIONAL, -- Cond SUL
prach-RootSequenceIndex CHOICE {
l839 INTEGER (0..837),
l139 INTEGER (0..137)
},
msg1-SubcarrierSpacing SubcarrierSpacing OPTIONAL, -- Cond L139
restrictedSetConfig ENUMERATED {unrestrictedSet, restrictedSetTypeA, restrictedSetTypeB},
msg3-transformPrecoder ENUMERATED {enabled} OPTIONAL, -- Need R
...,
[[
ra-PrioritizationForAccessIdentity-r16 SEQUENCE {
ra-Prioritization-r16 RA-Prioritization,
ra-PrioritizationForAI-r16 BIT STRING (SIZE (2))
} OPTIONAL, -- Cond InitialBWP-Only
prach-RootSequenceIndex-r16 CHOICE {
l571 INTEGER (0..569),
l1151 INTEGER (0..1149)
} OPTIONAL -- Need R
]],
[[
ra-PrioritizationForSlicing-r17 RA-PrioritizationForSlicing-r17 OPTIONAL, -- Cond InitialBWP-Only
featureCombinationPreamblesList-r17 SEQUENCE (SIZE(1..maxFeatureCombPreamblesPerRACHResource-r17)) OF FeatureCombinationPreambles-r17 OPTIONAL -- Cond AdditionalRACH
]],
[[
rach-ConfigAdapt-r19 RA-AdaptConfig-r19 OPTIONAL -- Need R
]]
}Fields (33)
| Field | Description |
|---|---|
| rach-ConfigGeneric RACH-ConfigGeneric since v15.1.0 | RACH parameters for both regular random access and beam failure recovery. |
| totalNumberOfRA-Preambles INTEGER (1..63) · OPTIONAL Need S since v15.1.0 | Total number of preambles used for contention based and contention free 4-step or 2-step random access in the RACH resources defined in RACH-ConfigCommon , excluding preambles used for other purposes (e.g. for SI request). If the field is absent, all 64 preambles are available for RA. The setting should be consistent with the setting of ssb-perRACH-OccasionAndCB-PreamblesPerSSB , i.e. it should be a multiple of the number of SSBs per RACH occasion. |
| ssb-perRACH-OccasionAndCB-PreamblesPerSSB CHOICE { · OPTIONAL Need M since v15.1.0 | The meaning of this field is twofold: the CHOICE conveys the information about the number of SSBs per RACH occasion. Value oneEighth 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 ). See TS 38.213 [13]. |
| oneEighth ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64} since v15.1.0 | |
| oneFourth ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64} since v15.1.0 | |
| oneHalf ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64} since v15.1.0 | |
| one ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32,n36,n40,n44,n48,n52,n56,n60,n64} since v15.1.0 | |
| two ENUMERATED {n4,n8,n12,n16,n20,n24,n28,n32} since v15.1.0 | |
| four INTEGER (1..16) since v15.1.0 | |
| eight INTEGER (1..8) since v15.1.0 | |
| sixteen INTEGER (1..4) since v15.1.0 | |
| groupBconfigured SEQUENCE { · OPTIONAL Need R | |
| ra-Msg3SizeGroupA ENUMERATED {b56, b144, b208, b256, b282, b480, b640, b800, b1000, b72, spare6, spare5,spare4, spare3, spare2, spare1} | 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). This field is set to the same value for different repetition numbers associated with a specific FeatureCombination . |
| messagePowerOffsetGroupB ENUMERATED { minusinfinity, dB0, dB5, dB8, dB10, dB12, dB15, dB18} | 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). This field is set to the same value for different repetition numbers associated with a specific FeatureCombination . |
| numberOfRA-PreamblesGroupA INTEGER (1..64) since v15.1.0 | The number of CB preambles per SSB in group A. This determines implicitly the number of CB preambles per SSB available in group B. (see TS 38.321 [3], clause 5.1.1). The setting should be consistent with the setting of ssb-perRACH-OccasionAndCB-PreamblesPerSSB . |
| ra-ContentionResolutionTimer ENUMERATED { sf8, sf16, sf24, sf32, sf40, sf48, sf56, sf64} | The initial value for the contention resolution timer (see TS 38.321 [3], clause 5.1.5). Value sf8 corresponds to 8 subframes, value sf16 corresponds to 16 subframes, and so on. |
| rsrp-ThresholdSSB RSRP-Range · OPTIONAL Need R since v15.1.0 | 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]). |
| rsrp-ThresholdSSB-SUL RSRP-Range · OPTIONAL Cond SUL since v15.1.0 | The UE selects SUL carrier to perform random access based on this threshold (see TS 38.321 [3], clause 5.1.1). The value applies to all the BWPs and all RACH configurations. |
| prach-RootSequenceIndex CHOICE { | PRACH root sequence index (see TS 38.211 [16], clause 6.3.3.1). The value range depends on whether L=839 or L=139 or L=571 or L=1151. The length of the root sequence corresponding with the index indicated in this IE should be consistent with the one indicated in prach-ConfigurationIndex in the RACH-ConfigDedicated (if configured). If prach-RootSequenceIndex-r16 is signalled, UE shall ignore the prach-RootSequenceIndex (without suffix). 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) | |
| msg1-SubcarrierSpacing SubcarrierSpacing · OPTIONAL Cond L139 since v15.1.0 | 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 absent, the UE applies the SCS as derived from the prach-ConfigurationIndex in RACH-ConfigGeneric (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]). The value also applies to contention free random access ( RACH-ConfigDedicated ), to SI-request and to contention-based beam failure recovery (CB-BFR). But it does not apply for contention free beam failure recovery (CF-BFR) (see BeamFailureRecoveryConfig ). |
| restrictedSetConfig ENUMERATED {unrestrictedSet, restrictedSetTypeA, restrictedSetTypeB} since v15.1.0 | Configuration of an unrestricted set or one of two types of restricted sets, see TS 38.211 [16], clause 6.3.3.1. |
| msg3-transformPrecoder ENUMERATED {enabled} · OPTIONAL Need R since v15.3.0 | Enables the transform precoder for Msg3 transmission according to clause 6.1.3 of TS 38.214 [19]. If the field is absent, the UE disables the transformer precoder (see TS 38.213 [13], clause 8.3). |
| ra-PrioritizationForAccessIdentity-r16 SEQUENCE { · OPTIONAL Cond InitialBWP-Only since v16.2.0 | |
| ra-Prioritization-r16 RA-Prioritization since v16.2.0 | 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)) since v16.2.0 | 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 indicates that the field ra-Prioritization-r16 applies otherwise the field does not apply (see TS 23.501 [32]). |
| prach-RootSequenceIndex-r16 CHOICE { · OPTIONAL Need R since v16.0.0 | PRACH root sequence index (see TS 38.211 [16], clause 6.3.3.1). The value range depends on whether L=839 or L=139 or L=571 or L=1151. The length of the root sequence corresponding with the index indicated in this IE should be consistent with the one indicated in prach-ConfigurationIndex in the RACH-ConfigDedicated (if configured). If prach-RootSequenceIndex-r16 is signalled, UE shall ignore the prach-RootSequenceIndex (without suffix). 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 |
| l571 INTEGER (0..569) since v16.0.0 | |
| l1151 INTEGER (0..1149) since v16.0.0 | |
| ra-PrioritizationForSlicing-r17 RA-PrioritizationForSlicing-r17 · OPTIONAL Cond InitialBWP-Only since v17.0.0 | Parameters which apply to configure prioritized CBRA 4-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 4-step RA. The network does not configure this list to have more than 16 entries. |
| rach-ConfigAdapt-r19 RA-AdaptConfig-r19 · OPTIONAL Need R since v19.1.0 | Parameters which apply to configure adaptive random access occasions. |
Used by (3)
Uses (8)
- FeatureCombinationPreambles-r17
- RA-AdaptConfig-r19
- RA-Prioritization
- RA-PrioritizationForSlicing-r17
- RACH-ConfigGeneric
- RSRP-Range
- SubcarrierSpacing
- maxFeatureCombPreamblesPerRACHResource-r17