LTM-Config (LTM-Config-r18)

RRC IE · TS 38.331 v19.4.0 (2026-09) · clause 6.3.2

LTM-Config-r18 is an RRC information element of 3GPP TS 38.331 (38331), the 5G NR Radio Resource Control (RRC) protocol.

First seen v18.0.0 (2024-01) · Last changed v19.1.0 (2026-01)

Definition

The IE LTM-Config is used to provide LTM configurations.

LTM-Config-r18 ::=   SEQUENCE {
    ltm-ReferenceConfiguration-r18        SetupRelease {ReferenceConfiguration-r18}                             OPTIONAL,   -- Need M
    ltm-CandidateToReleaseList-r18        SEQUENCE (SIZE (1..maxNrofLTM-Configs-r18)) OF LTM-CandidateId-r18    OPTIONAL,   -- Need N
    ltm-CandidateToAddModList-r18         SEQUENCE (SIZE (1..maxNrofLTM-Configs-r18)) OF LTM-Candidate-r18      OPTIONAL,   -- Need N
    ltm-ServingCellNoResetID-r18          INTEGER (1..maxNrofLTM-Configs-plus1-r18)                             OPTIONAL,   -- Need N
    ltm-CSI-ResourceConfigToAddModList-r18  SEQUENCE (SIZE (1..maxNrofLTM-CSI-ResourceConfigurations-r18)) OF LTM-CSI-ResourceConfig-r18
    OPTIONAL,   -- Need N
    ltm-CSI-ResourceConfigToReleaseList-r18 SEQUENCE (SIZE (1..maxNrofLTM-CSI-ResourceConfigurations-r18)) OF LTM-CSI-ResourceConfigId-r18
    OPTIONAL,   -- Need N
    attemptLTM-Switch-r18                 ENUMERATED {true}                                                    OPTIONAL, -- Cond LTM-MCG
    ltm-ServingCellUE-MeasuredTA-ID-r18   INTEGER (1..maxNrofLTM-Configs-plus1-r18)                             OPTIONAL,   -- Need N
    ...,
    [[
        ltm-ServingCellNoSecurityChangeID-r19   LTM-NoSecurityChangeId-r19                                          OPTIONAL,   -- Need N
        ltm-ServingCellExecutionCondition-r19   CHOICE {
            release                                 NULL,
            setup                                   LTM-ExecutionConditionList-r19
        }                                                                                                           OPTIONAL    -- Need N
    ]]
}

Candidate change requests of v19.1.0

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

CR 5593 r2 (strong): Corrections on RRC for mobility enhancements Phase 4
CR 5530 r2 (likely): Introducing SR resources in LTM cell switch MAC CE [LTM_enh_SR]
CR 5558 r3 (likely): Correction on the execution of SCG LTM

Fields (12)

Field	Description
ltm-ReferenceConfiguration-r18 SetupRelease {ReferenceConfiguration-r18} · OPTIONAL Need M
ltm-CandidateToReleaseList-r18 SEQUENCE (SIZE (1..maxNrofLTM-Configs-r18)) OF LTM-CandidateId-r18 · OPTIONAL Need N
ltm-CandidateToAddModList-r18 SEQUENCE (SIZE (1..maxNrofLTM-Configs-r18)) OF LTM-Candidate-r18 · OPTIONAL Need N
ltm-ServingCellNoResetID-r18 INTEGER (1..maxNrofLTM-Configs-plus1-r18) · OPTIONAL Need N
ltm-CSI-ResourceConfigToAddModList-r18 SEQUENCE (SIZE (1..maxNrofLTM-CSI-ResourceConfigurations-r18)) OF LTM-CSI-ResourceConfig-r18 · OPTIONAL Need N
ltm-CSI-ResourceConfigToReleaseList-r18 SEQUENCE (SIZE (1..maxNrofLTM-CSI-ResourceConfigurations-r18)) OF LTM-CSI-ResourceConfigId-r18 · OPTIONAL Need N
attemptLTM-Switch-r18 ENUMERATED {true} · OPTIONAL Cond LTM-MCG
ltm-ServingCellUE-MeasuredTA-ID-r18 INTEGER (1..maxNrofLTM-Configs-plus1-r18) · OPTIONAL Need N
ltm-ServingCellNoSecurityChangeID-r19 LTM-NoSecurityChangeId-r19 · OPTIONAL Need N since v19.0.0
ltm-ServingCellExecutionCondition-r19 CHOICE { · OPTIONAL Need N since v19.0.0	This field can can only be included in an ltm-Config associated with the MCG.
release NULL since v19.1.0
setup LTM-ExecutionConditionList-r19 since v19.1.0

LTM-Config (LTM-Config-r18)

Definition

Candidate change requests of v19.1.0

Fields (12)

Used by (2)

Uses (11)

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