This was the first RAN3 meeting to host 6G Study Items on the agenda alongside the usual NG-RAN protocol upkeep. The End-of-Meeting (EoM) agenda shows dedicated “Study on 6G Radio (FS_6G_Radio)” blocks (AI 10.x), explicit deliverables RAN3 must prepare for TSG decisions (e.g., RAN-CN interface: P2P vs SBI; RAN internal interfaces: CU–DU and CP–UP splits), and a RAN3-endorsed working principle to keep 6G standards lean and avoid option bloat. An offline CB: “6G RAN-CN” also ran during the week.

At the same time, the chairs’ notes document tangible decisions in the “bread-and-butter” areas that hit stacks quickly: Alternative QoS (AQP) averaging window, per-UE performance metrics alignment, Continuous MDT signalling over Xn, mobility/LTM details across Xn/F1/E1, plus Reply LS to IETF TEAS to keep terminology strictly 3GPP-aligned. These will surface as CRs in NGAP/XnAP/F1AP/E1AP and Stage-2 soon.

TL;DR

• 6G kicks off in RAN3: First WG meeting with explicit 6G Study Item time blocks and an offline CB on RAN–CN. Scope set to study RAN–CN interface options (P2P vs SBI) and internal splits (CU–DU, CP–UP) under a “lean standards” principle (minimise options).
• No 6G stage-3 yet: Work is at study/scoping level pending Stage-1/2 and TSG Way-Forward. Interim results targeted ~TSG#112 (mid-2026) before any protocol text.
• AQP averaging window decided: Use the active QoS profile’s averaging window to judge fulfilment/select alternatives (“Understanding 1”). CRs expected across NGAP (38.413), XnAP (38.423), F1AP (38.473), E1AP (37.483) for Rel-18/19; Reply-LS → SA2.
• Per-UE performance metrics aligned: Clarify drop vs loss (DL), add UL Average Packet Loss with TS 28.558references; XnAP/E1AP CRs queued and LS → SA5 to lock aggregation semantics.
• C-MDT over Xn HO: Direction to add a new IE in Xn HO Request/Retrieve UE Context Response indicating management-based C-MDT (ties to NG-RAN Trace ID). Security/prioritisation open with SA3/SA5; 38.423/38.413/38.401 updates to follow.
• Trace temporary suspension (R19): Feasibility only; Reply-LS → SA5 approved-unseen; RAN3 won’t designRel-19 solutions here.
• Mobility & LTM (incl. inter-CU): Progress on CSI-RS/CSI-IM resource transfer, CFRA/PRACH for RACH-less LTM, early data forwarding, UE association info → CRs across XnAP/F1AP and 38.401.
• IETF TEAS reply: Reassert DU/CU-UP/F1-U and NG-RAN figures as 3GPP/RAN3; flag non-3GPP terms (FH/MH) and fix inconsistencies.
• WAB / NR-Femto / LTE-NTN: Multiple Rel-19 corrections endorsed/merged (NGAP/XnAP/38.401; LTE 36.413/36.443); some proposals parked as new functionality.
• What to watch next: Incoming CR drops in 38.413/38.423/38.473/37.483 (+ 38.401), LS threads with SA2/SA5, and 6G interim deliverables that trigger the first stage-3 asks.

6G enters RAN3: what started—and what didn’t (yet)

Scope

• Study on 6G Radio (FS_6G_Radio): RAN3 kicked off its 6G track under the FS_6G_Radio study, anchoring to usage scenarios / requirements / deployment (per TR 38.914 lineage) and targeting interim study results for TSG#112 (June 2026). Those interim results are explicitly meant to inform TSG decisions on:
  • RAN–CN interface model: Point-to-Point (P2P) vs Service-Based Interface (SBI)
  • RAN internal interfaces/splits: CU–DU and CP–UP demarcations for 6GChairs also recorded the “lean standards” principle for 6G (minimise options; require justification for exceptions), to contain complexity early.
• Workplan hygiene: A RAN3 workplan paper for Rel-20 6G study (R3-256939) was edited in the room: remove the line “Mobility between 5G and 6G” from the per-meeting text and soften phrasing to “framework based on identified use cases.” A revised version (R3-257233) was noted.
• Liaison context entering 6G: Incoming LSs were tabled on spec modernisation for 6G (R3-256532, SA), 6G data work guidance (R3-256533, SA), and 6G fronthaul (R3-256536, RAN). The fronthaul LS was minuted as: RAN3 will follow the TSG RAN Way-Forward during the normative phase—i.e., no unilateral stage-3 design in WG3 before plenary direction.
• Theme primers (discussion papers noted by the chairs as inputs to scope):
  • General principles & requirements for 6G RAN: e.g., R3-256571 (multi-company) and R3-256615(CATT)
  • Service-aware RAN architecture options: R3-256716 (T-Mobile) — keep support for RAN service characteristics/awareness; don’t confine scope to real-time services (Vodafone remark recorded).
  • Emergency services in 6G: R3-256718 (T-Mobile) — RAN3 shall study interface & function requirements for E911 over 6G; be mindful of mission-critical services.
  • RAN data in 6G: R3-256846 (CMCC) — drive toward a unified data-collection framework; note the likely different RAN–Core functional split in 6G.

Meeting logistics (how the agenda carved out 6G)

• The agenda dedicated AI 10.x to 6G:
  • 10.1 General — rapporteur inputs (workplan, draft TR 38.xxx) and LSs
  • 10.2 Overall RAN architecture — QUOTA: 2, based on standalone architecture; proposals must be requirement-motivated
    • 10.2.1 General principles & requirements
    • 10.2.2 RAN functions & logical architecture
  • 10.3 RAN–CN interface — QUOTA: 2
    • 10.3.1 General principles & requirements
    • 10.3.2 Interface options — describe principal options; identify required studies contingent on progress in principles/requirements
  • 10.4 RAN internal functional split & interfaces — QUOTA: 1
  • 10.5 AI/ML for RAN — QUOTA: 1, leverage 5G AI/ML framework (TR 38.843) where appropriate
• An offline CB labelled “6G RAN–CN” ran during the week—i.e., explicit WG time was allocated for 6G architecture discussions in addition to plenary slots.

What RAN3 did (and didn’t) do this week

• Did (scoping & guard-rails set):
  • Opened RAN–CN interface discussions with multiple principle/requirement TDocs (e.g., R3-256590Huawei/Jio, R3-256779 NEC, R3-256811 InterDigital, R3-256906 Lenovo, R3-257051 LG, R3-257063Ericsson, R3-256624 Xiaomi, R3-256540 ZTE, R3-256575 Qualcomm et al.). The notes repeatedly stress coordination with SA2 on function allocation and that traffic/control/data transmission expectations across a new interface must be explicitly defined.
  • Laid down internal-split study hooks (e.g., R3-256630 Nokia; R3-256577 Qualcomm; R3-256583 China Telecom; R3-256801 NEC; R3-256897 Rakuten/Samsung; R3-256971 China Unicom; R3-257122 LG). The chair’s note on R3-256630 captures the stance: wait with CP–UP split study and study whether/how higher-layer splits are supported for 6G.
  • Captured early P2P vs SBI groundwork (e.g., R3-256940 Vodafone on SBI & P2P definitions; R3-256887Nokia on an enhanced P2P solution).
  • Recorded E911 over 6G as a RAN3 study responsibility (interface + functions), with sensitivity to mission-critical hooks.
  • Reaffirmed lean-standards as a working principle and plenary Way-Forward alignment (e.g., for 6G fronthaul).
• Did not (yet):
  • No stage-3 protocol text for 6G was started in NGAP/XnAP/F1AP/E1AP (or new 6G APs). The chairs consistently kept 6G at study level, pending stage-1/2 maturation and TSG decisions on the architecture/splits.

Takeaway

Treat #129-bis as Day-0 for RAN3’s 6G architecture track: the WG has now formalised scope, agenda structure, quotas, and CB time, and logged a first wave of principles/requirements papers across RAN–CN interface, internal splits, service-awareness, data, and public-safety. If your teams touch CU/DU evolution, CP/UP demarcation, P2P/SBI trade-offs, service-aware control, or data-collection architectures, start internal straw-man analyses and requirements mapping now. Expect the first normative asks only after interim study results (~TSG#112, mid-2026), when TSG locks the architecture direction and RAN3 can translate it into stage-3.

Other Topics

1) Alternative QoS (AQP): averaging window resolved

Decision: Use the averaging window of the currently active QoS profile to judge fulfilment and select an alternative. Treat a per-AQP-set window as new requirement. Chairs recorded broad consensus (“Understanding 1”) and queued a Reply LS to SA2.

How it appeared in the agenda:

• R3-256515 — LS on Average Window for Alternative QoS (from SA2 / CICT Mobile) → LS-in, Noted
• R3-256645 — Discussion on LS on Average Window for AQP (CATT) → Discussion, Noted
• R3-256646 — Correction… for NGAP (CATT) with CR1323r to TS 38.413 (Rel-18 Cat.F) → noted in chairs’ notes
• Mirror CRs were queued/mentioned for XnAP 38.423 (e.g., CR1523r family), F1AP 38.473 (e.g., CR1588rfamily), and E1AP 37.483 (e.g., CR0177r) across Rel-18/Rel-19.

Spec impact to watch: 38.413 / 38.423 / 38.473 / 37.483 (Rel-18 Cat.F & Rel-19 Cat.A variants).

2) Per-UE performance metrics: align with SA5 (TS 28.558), add UL metric

Decisions captured in notes:

• Rename Average Packet Loss DL → Average Packet Drop DL; add explicit TS 28.558 clause reference for the DL drop rate.
• Introduce UL Average Packet Loss (new IE) with normative TS 28.558 reference for the UL loss rate.
• Aggregation method (per-UE vs per-DRB) generated debate; expect a Reply LS to SA5 to lock semantics and avoid interop drift.

How it appeared in the agenda (exemplary entries):

• R3-256518 — Reply LS on per-UE performance metrics (SA5 / Huawei) → LS-in, Noted
• R3-256973 — Further discussion on per-UE metrics (Huawei, FiberCop, BT, Jio) → Discussion, Noted
• R3-256999 — CRs on UE metrics in XnAP (Huawei et al.) → CRs referenced (e.g., CR1562r/-63r/-64r/-65r, CR1567r/-68r, CR1547r/-48r, CR1556r/-57r)
• R3-2570xx — E1AP mirror CRs → E1AP 37.483 (CR0176r/-80r) called out in notes

Spec impact: a packet of XnAP 38.423 and E1AP 37.483 CRs endorsed/queued, plus LS-outs to SA5.

3) Continuous MDT (C-MDT): signal it in Xn handovers

Direction agreed: Add a new IE in Xn: Handover Request and Xn: Retrieve UE Context Response to indicate management-based C-MDT, referencing the existing NG-RAN Trace ID.

Open points in notes: prioritisation vs signalling-based MDT, de-configuration semantics, and security touch-points (SA3/SA5).

Representative entries:

• R3-256938 — C-MDT signalling considerations → Discussion with direction to add new IE(s)
• R3-257098 / R3-257099 — draft CR pointers for XnAP 38.423 and cross-refs to 38.413 / 38.401 → in flight

Spec impact: 38.423 / 38.413 / 38.401 (CRs already in motion).

4) Trace “temporary suspension” (Rel-19): feasibility only

Outcome: Reply LS to SA5 approved-unseen, clarifying RAN3 does not design solutions in Rel-19; Logged-MDTapplicability flagged.

Representative entries:

• R3-257071 — Reply LS on temporary suspension of Trace → Approved-unseen (title/cover-page tidy-ups recorded)

5) IETF TEAS “Network Slice Application”: boundaries reaffirmed

Reply LS content (approved-unseen):

• Point TEAS to TS 38.401; clarify DU/CU-UP/F1-U and the NG-RAN figures are 3GPP/RAN3 definitions.
• Note that FH/MH terms are not 3GPP.
• Enumerate figure/text inconsistencies for correction.

Representative entries:

• R3-256636 / R3-256637 — Reply LS to IETF TEAS on Network Slice Application → Approved-unseen in notes

6) Mobility & LTM (incl. inter-CU): resource transfer & early forwarding

Notes highlight: a sizeable LTM cluster advanced, including:

• CSI-RS / CSI-IM resource transfer semantics for inter-CU LTM,
• CFRA / PRACH resources for RACH-less LTM,
• Early Data Forwarding and UE association info.

Representative entries (exemplary):

• R3-2569xx / R3-2570xx — multiple XnAP/F1AP CRs, e.g.
  • XnAP 38.423: CR1549r, CR1551r, CR1560r families (resource-transfer/association info)
  • F1AP 38.473: CR1625r, CR1628r (procedure refinements, abnormal conditions)
  • Stage-2 38.401: CR0499r (procedure hooks)
• Statuses across items include Discussion, Endorsed, Endorsed-unseen, and a few draftCR placeholders.

Spec impact: 38.423 / 38.473 / 38.401.

7) WAB & NR-Femto: corrections continue

Outcome: Several Rel-19 corrections across NGAP/XnAP/38.401 were endorsed/merged; some proposals were judged “new functionality” and parked. Femto clarifications (paging/verification/security) appear as NGAP (38.413) CRs.

Representative entries:

• R3-2569xx — WAB corrections → Merged / Endorsed
• R3-25697x / R3-25713x — NR-Femto paging/verification/security → 38.413 (CR1345r, CR1367r) endorsed

8) LTE carry-overs for IoT-NTN

Focus: S1 removal clarifications, TNL addressing, and MME Name IE criticality.

Outcome: draftCRs refined; Endorsed-unseen, with explicit note to set MME Name IE → ignore in 36.413.

Representative entries:

• R3-2566xx / R3-2567xx — LTE S1 removal / NTN addressing → 36.413 Cat.F clean-ups, Endorsed-unseen

9) Ambient-IoT (A-IoT) touch-ups (Rel-19)

Outcome: CRs endorsed in 38.413 (interface-management, IE encoding) and 38.401; several LS-ins from SA/CT were Noted to keep alignment.

Representative entries:

• R3-256634 — Corrections to A-IoT context definition → 38.401 CR0481r (Rel-19 Cat.F) — support noted
• R3-256642 — Correction on A-IoT leftovers on IE details → 38.413 CR1321r (Rel-19 Cat.F) — Endorsed
• R3-256500 / R3-256504 — LS-ins on AIoT container size/handling (CT1) → LS-in, Noted

Reading chairs’ notes like a standards engineer

• Action words drive urgency: Discussion, Endorsed (unseen), Approved (unseen), Merged, Noted, draftCR → translate directly to what your team does next (draft pCRs, start interop vectors, or hold pending LS). The EoM doc also codifies quota rules, CB etiquette, and colour coding for scheduling and priorities—useful for planning your paper queue.
• Trace dependencies: LS-ins/outs are explicitly logged (e.g., AQP → SA2, UE-metrics/MDT → SA5) and often include who moderates the CB and where to park drafts. That tells you where consensus will harden next.

Spec-impact cheat-sheet (what to watch)

• NGAP (TS 38.413): AQP averaging window; WAB/Femto tweaks; C-MDT touch-points; NTN suspend/resume hooks.
• XnAP (TS 38.423): UE-metrics (DL rename, UL loss IE), C-MDT IEs in HO, LTM resource-transfer, data-collection clean-ups.
• F1AP (TS 38.473): AQP alignment, mobility/LTM procedures (incl. abnormal conditions), PDCP discard timer options.
• E1AP (TS 37.483): UE-metrics semantics alignment; AQP mirror CRs.  
• Stage-2 (TS 38.401 / 38.455): LTM, positioning RS corrections, C-MDT split-arch hooks.  
• LTE (36.413/36.443): S1-removal corrections & IE criticality.

☑️ Recap

• 6G in RAN3 formally starts here. The #129-bis agenda carved out AI 10.1–10.5 for 6G Study Item work and ran an offline CB: “6G RAN-CN.” Chairs logged the lean-standards principle (limit options, justify exceptions) and set deliverables toward interim study results by TSG#112 (~June 2026) to decide RAN–CN interface (P2P vs SBI) and RAN internal splits (CU–DU, CP–UP).
• Reality check on near-term coding: The items you’ll actually implement before mid-2026 are the protocol hygiene and Rel-19 changes that moved this week:
  • AQP averaging window → “Understanding 1” (use the active profile’s averaging window) with CRs queued across NGAP 38.413 / XnAP 38.423 / F1AP 38.473 / E1AP 37.483 (e.g., 38.413: CR1323r; mirrors expected in 38.423/38.473/37.483).
  • Per-UE performance metrics → align terminology to TS 28.558 (DL drop vs loss), add UL Average Packet Loss IE; multiple XnAP (CR1562r/-63r/-64r/-65r, CR1567r/-68r, CR1547r/-48r, CR1556r/-57r) and E1AP (CR0176r/-80r) changes noted; Reply-LS → SA5 to lock aggregation/semantics.
  • C-MDT on Xn HO paths → new IE in Xn HO Request / Retrieve UE Context Response, referencing NG-RAN Trace ID; follow-ups span 38.423 / 38.413 / 38.401 (prioritisation vs signalling-MDT, de-config, SA3/SA5 security touch-points).
  • Trace temporary suspension (Rel-19) → Reply-LS → SA5 approved-unseen; RAN3 won’t design Rel-19 solutions here; Logged-MDT applicability flagged.
  • IETF TEAS “Network Slice Application” → Reply-LS approved-unseen: reaffirm DU/CU-UP/F1-U and NG-RAN figures as 3GPP/RAN3, note FH/MH are not 3GPP; request figure/text fixes; point to TS 38.401.
  • Mobility & LTM (incl. inter-CU) → progress on CSI-RS/CSI-IM resource transfer, CFRA/PRACH for RACH-less LTM, early data forwarding, UE association info with CRs across 38.423 / 38.473 / 38.401.
  • WAB & NR-Femto → several Rel-19 corrections endorsed/merged (NGAP/XnAP/38.401); Femto paging/verification/security refinements in 38.413 (e.g., CR1345r, CR1367r); proposals deemed “new functionality” were parked.
  • LTE carry-overs for IoT-NTN → S1 removal, TNL addressing, MME Name IE → ignore (36.413) endorsed-unseen.
  • Ambient-IoT (A-IoT) → corrections endorsed in 38.413 & 38.401; related LS-ins from SA/CT noted to keep alignment.
• Process signals from the EoM notes (useful for planning):
  • Volume: ~678 agenda rows parsed; CR mentions ≥ 300 (heaviest in XnAP, then F1AP, NGAP, 38.401, E1AP).
  • Liaisons: ~29 LS-in and ~17 LS-out/Reply-LS recorded.
  • Statuses (approx.): Discussion dominated, with many endorsed/endorsed-unseen, some merged, a few approved, and the usual carry-over/draftCR placeholders.
• Actionable watchlist (engineer’s view):
  • Track AQP/metrics/C-MDT/LTM CR drops into 38.413 / 38.423 / 38.473 / 37.483 (+ 38.401).
  • Follow the SA2 (AQP) and SA5 (metrics/MDT/trace) LS threads to freeze semantics before IOT.
  • Prepare regression vectors:
    • AQP fulfilment under mixed profile timers,
    • UL loss metrics ingestion & OAM export,
    • Xn HO with C-MDT flag on/off,
    • LTM inter-CU resource-transfer edge cases (CFRA/PRACH, early forwarding).

Primary source: RAN3 #129-bis End-of-Meeting agenda with per-contribution chairs’ notes (Prague, 13–17 Oct 2025).