3GPP RAN2 #132 (Dallas): Rel-18 correction wave, Rel-19 AI/ML air-interface tightening, and first-pass 6G radio study framing

TL;DR

• 1,213 TDocs were tracked across the week: 842 discussion items, 296 CR/draftCR items, 44 liaisons (in/out), plus admin/reporting items.
• The docket skewed toward Rel-19 (482) and Rel-20 (436), reflecting heavy feature/study-item load alongside the correction phase.
• Most-touched specs in the CR stream were 38.331 (RRC), 38.306 (UE caps), and 38.321 (MAC).
• 6G work showed up strongly through FS_6G_Radio, with captured study directions on UE capability framework, modular RRC (re)configuration, data/model transfer, and energy efficiency, aligned with the “lean standards” principle.

RAN2 met in Dallas (Nov 17–21, 2025) with the usual procedural reminders (IPR, antitrust, contribution discipline) and a clear steering signal for 6G: keep the standard lean, minimize parallel options, and justify exceptions.

By the numbers

Rel-coverage was dominated by Rel-19 and Rel-20, with a smaller but still important Rel-18 correction volume. In the CR stream, the densest spec touchpoints were 38.331, 38.306, and 38.321, consistent with the meeting’s center of gravity on RRC procedures, capability signaling, and MAC behavior clarifications.

Housekeeping and procedural anchors

The week started cleanly: the agenda was approved under R2-2508001.
The broader process guidance reinforced a tighter correction workflow: one correction CR per spec per feature coordinated through editors/rapporteurs, explicit open-issue tracking, and an emphasis on resolving what can be resolved offline without spinning new contribution cycles.

LTE and IoT NTN maintenance: clarifying edge conditions

LTE/IoT NTN corrections focused on clarifying boundary behaviors where power, bandwidth, and timing advance reporting can become ambiguous in NTN operation. This thread is visible across the 36.331 correction set, with revisions and aligned parallel-Release handling tracked through the IoT NTN entries like R2-2508039, R2-2508747/8748/8749, and the follow-on aligned versions R2-2509095/9096/9097 (TA reporting) as well as the maximum-power/bandwidth clarifications R2-2509098/9094/9099.

NR baseline corrections (Rel-15–17): RRC/MAC consistency fixes that propagate

Several “small” clarifications have large blast radius because they sit in foundational specs and touch multiple releases:

• Stage-2 baseline restriction clarity (38.300): the single-SCS-per-frequency restriction was maintained consistently across releases via R2-2508534–R2-2508538, keeping the interpretation aligned from Rel-15 through Rel-19.
• Sidelink MAC header correctness (38.321): the correction to the F field in the MAC subheader for SL-SCH was carried across releases with the revised set R2-2509162–R2-2509165, while earlier versions R2-2509020–R2-2509023 were withdrawn.
• RRC configuration clarity (38.331): the “SSB-less SCell” clarification was kept aligned from Rel-15 to Rel-19 via R2-2508725–R2-2508729, which is exactly the kind of RRC interpretation issue that can otherwise fragment UE/network expectations over time.

Rel-17 also carried targeted correctness repairs in RRC:

• SCS-Specific Carrier value correctness via R2-2508305/8306/8307, with the Rel-19 revision tracked under R2-2509142.
• A Stage-2 hygiene pass for MUSIM turned an editor note into normative text through R2-2508195–R2-2508197.

Rel-18 corrections: converging behavior across mobility, positioning, XR, relay, energy, QoE

Rel-18’s correction load leaned into the practical engineering work: remove ambiguity, align dependent specs, and make procedures testable.

Mobility and LTM

• SCG LTM execution correctness was handled through the paired corrections R2-2508088 (Rel-18) and R2-2508089 (Rel-19 tracking for the same topic).
• LTM capability and behavior alignment was reinforced with the revised UE-capability corrections R2-2509125/9126 and related mobility correction cluster entries under the Rel-18 common stream.
• A dedicated “remaining issues” consolidation for LTM was explicitly approved in R2-2508716, signaling closure on at least the named open items in that package.

Positioning

• Cross-cutting positioning correctness for LPHAP, carrier phase, bandwidth aggregation and hopping landed via R2-2508120 (Rel-18) and R2-2508121 (Rel-19 Cat-A tracking).
• UTW capability consistency across positioning SRS frequency hopping was tightened through the aligned set in 37.355/38.306/38.331: R2-2508166–R2-2508171.
• NCD-SSB configuration for positioning was corrected via R2-2508983/8984, while RRC-inactive positioning corner cases (autonomous TA adjustment and stored RSRP update) were addressed via R2-2508604/8605 and R2-2508606/8607.

XR and traffic reporting

XR correctness focused on MAC behavior and reporting triggers:

• DSR triggering correctness: R2-2508256 (Rel-18) and R2-2508257 (Rel-19).
• Delay status report MAC CE correction: R2-2508393.

Sidelink relay

Sidelink relay continued to mature through both stage-2 control-plane procedures and RRC fixes:

• U2U relay control plane procedures: R2-2508772/8773.
• Indirect path failure information measurement results: R2-2508898/8899.

Energy efficiency and QoE hygiene

• NR energy-saving behaviors (DRX/DTX-related corner cases) were tightened via R2-2508512/8513 and the UE-transmission-during-Cell-DRX pair R2-2508515/8517 with their stage-2 mirrors in 38.300 (R2-2508516/8518).
• QoE-related configuration correctness was tracked with the SRB4/SRB5 PDCP configuration corrections (Rel-19 revision captured in R2-2509133) and the QoE reporting corrections R2-2509013/9067.

Rel-19: AI/ML air-interface work and “TEI19” convergence points

Rel-19’s AI/ML air-interface thread showed concrete lifecycle-management and applicability handling discussions, with explicit convergence where noted.

• A positioning-related AI/ML correction was marked agreed in R2-2508103.
• TEI19 recorded two clean “agreed” CRs around early CSI acquisition and its capability support: R2-2509309 and R2-2509310.
• The ASN.1 review stream endorsed naming alignment for Rel-19 parameter lists in R2-2509343, reducing long-term friction between spec text and generated encodings.

Liaison handling also advanced: the reply LS on the updated RAN1 UE feature list was approved as R2-2509345, and the reply LS on service-collision handling was approved as R2-2509384.

Rel-20 / 6G radio study: modularity, data/model transfer, energy, and TN/NTN integration under the “lean” principle

The 6G-facing work (tracked heavily under FS_6G_Radio) concentrated on building a workable framing without locking into stage-3 style protocol text prematurely.

Work plan and scope discipline

• The 6G SI work plan was explicitly noted in R2-2509078, grounding the follow-on technical threads in a shared structure.

UE capability framework

A dense set of contributions captured study directions around capability structure, update behavior, and interoperability risk:

• Capability pain points and considerations were consolidated through R2-2508076, with follow-on framing and alternatives under R2-2508903, R2-2508422, and R2-2508322.

Modular RRC structure and (re)configuration

The “modularization” theme was repeatedly stressed in the RRC structure track:

• Modular design and partitioning concepts were captured across R2-2509077, R2-2508098, R2-2508080, and the ASN.1/encoding angle in R2-2508115.

Data transfer, model transfer, and AI/ML framework

The data/model transfer discussions leaned into baseline assumptions and transport characteristics rather than over-optimizing prematurely:

• Captured proposals and baseline requirements appeared across R2-2508082, R2-2508576, R2-2509054, R2-2508335, and R2-2509012. Several related entries were later marked withdrawn, which signals consolidation pressure rather than abandonment of the topic.

Energy efficiency

Energy work emphasized RRC-state-aware mechanisms and study items around DTX/DRX and wake-up concepts:

• The energy efficiency direction is visible in R2-2508410, R2-2508243, R2-2508519, and the LP-WUS/WUR linkages called out in R2-2508940.

TN/NTN integration

The TN/NTN thread stayed prominent as a 6G design constraint rather than a bolt-on:

• Integration assumptions and harmonization requirements were discussed through R2-2508295, R2-2508639, R2-2508777, and a dedicated integration discussion entry R2-2509006.

Closing

Overall, it was a week optimized for correction-phase throughput: heavy CR volume on RRC, UE capability signaling, and MAC correctness; explicit revision control to keep contributions unambiguous; and strong agenda structuring for Rel-20/6G studies that applies a lean-standards constraint while deferring premature architectural splits.