CFRA

RRC IE · TS 38.331 v19.4.0 (2026-09) · clause 6.3.2, in the RACH-ConfigDedicated clause

CFRA is an RRC information element of 3GPP TS 38.331 (38331), the 5G NR Radio Resource Control (RRC) protocol.

First seen v15.2.0 (2018-06) · Last changed v19.1.0 (2026-01)

Definition

CFRA ::=                    SEQUENCE {
    occasions                       SEQUENCE {
        rach-ConfigGeneric              RACH-ConfigGeneric,
        ssb-perRACH-Occasion            ENUMERATED {oneEighth, oneFourth, oneHalf, one, two, four, eight, sixteen}
        OPTIONAL  -- Cond Mandatory
    }                                                                                                       OPTIONAL, -- Need S
    resources                       CHOICE {
        ssb                             SEQUENCE {
            ssb-ResourceList                SEQUENCE (SIZE(1..maxRA-SSB-Resources)) OF CFRA-SSB-Resource,
            ra-ssb-OccasionMaskIndex        INTEGER (0..15)
        },
        csirs                           SEQUENCE {
            csirs-ResourceList              SEQUENCE (SIZE(1..maxRA-CSIRS-Resources)) OF CFRA-CSIRS-Resource,
            rsrp-ThresholdCSI-RS            RSRP-Range
        }
    },
    ...,
    [[
        totalNumberOfRA-Preambles INTEGER (1..63)                                                             OPTIONAL -- Cond Occasions
    ]],
    [[
        msg1-RepetitionNum-r18          ENUMERATED {n2, n4, n8, spare1}                                               OPTIONAL -- Cond 4StepCFRArep
    ]],
    [[
        ra-OccasionType-r19             ENUMERATED {sbfd}                                                             OPTIONAL  -- Need S
    ]]
}

Candidate change requests of v19.1.0

The CRs whose title or cover names this change, strong and likely matches only.

CR 5499 r3 (strong): Corrections to WI SBFD

Fields (13)

Field	Description
occasions SEQUENCE { · OPTIONAL Need S	RA occasions for contention free random access. If the field is absent, the UE uses the RA occasions configured in RACH-ConfigCommon in the first active UL BWP.
rach-ConfigGeneric RACH-ConfigGeneric	Configuration of contention free random access occasions for CFRA. The UE shall ignore preambleReceivedTargetPower , preambleTransMax , powerRampingStep , ra-ResponseWindow signaled within this field and use the corresponding values provided in RACH-ConfigCommon .
ssb-perRACH-Occasion ENUMERATED {oneEighth, oneFourth, oneHalf, one, two, four, eight, sixteen} · OPTIONAL Cond Mandatory	Number of SSBs per RACH occasion.
resources CHOICE {
ssb SEQUENCE {
ssb-ResourceList SEQUENCE (SIZE(1..maxRA-SSB-Resources)) OF CFRA-SSB-Resource
ra-ssb-OccasionMaskIndex INTEGER (0..15)	Explicitly signalled PRACH Mask Index for RA Resource selection in TS 38.321 [3]. The mask is valid for all SSB resources signalled in ssb-ResourceList . The UE shall ignore this field if the field msg1-RepetitionNum included in CFRA is configured.
csirs SEQUENCE {
csirs-ResourceList SEQUENCE (SIZE(1..maxRA-CSIRS-Resources)) OF CFRA-CSIRS-Resource
rsrp-ThresholdCSI-RS RSRP-Range
totalNumberOfRA-Preambles INTEGER (1..63) · OPTIONAL Cond Occasions since v15.8.0	Total number of preambles used for contention free random access in the RACH resources defined in CFRA, excluding preambles used for other purposes (e.g. for SI request). If the field is absent but the field occasions is present, the UE may assume all the 64 preambles are for RA. The setting should be consistent with the setting of ssb-perRACH-Occasion , if present, i.e. it should be a multiple of the number of SSBs per RACH occasion.
msg1-RepetitionNum-r18 ENUMERATED {n2, n4, n8, spare1} · OPTIONAL Cond 4StepCFRArep since v18.0.0	Indicates the MSG1 repetition number used for contention free 4-step random access type in TS 38.321 [3]. If this field is absent, the UE performs contention free 4-step random access without MSG1-Repetitions.
ra-OccasionType-r19 ENUMERATED {sbfd} · OPTIONAL Need S since v19.1.0	Indicates that SBFD aware UE (see TS 38.300 [2], clause 23.1) shall use the second PRACH occasions (see TS 38.213 [13], clause 8) for CFRA or for the fallback CBRA, as specified in clause 5.1.2 in TS 38.321 [3]. If absent, the first PRACH occasions shall be used.

Used by (1)

RACH-ConfigDedicated

CFRA

Definition

Candidate change requests of v19.1.0

Fields (13)

Used by (1)

Uses (6)

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