S4-260011 - AI Proposals

Reply LS on the RAN simulation assumptions for ULBC

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Proposal 1: RAN1 generally agrees with the overall set of parameters selected by SA4, with the following comments:

  • On the modulation order, RAN1 would like to highlight that MCS indices 0 and 1 use pi/2 BPSK for single tone transmissions. It is up to SA4 to decide whether to evaluate pi/2 BPSK with MCS indices 0 and 1.

  • For the downlink CNR, the relevant UE parameter is noise figure (and/or G/T) instead of transmit power. RAN1 recommends SA4 corrects the following sentence:

DL CNR=-3.3dB, 0dBi UE antenna gain, 15kHz SCS, 12 tones, 1 UE receive antenna, noise figure of 7dB.

  • If SA4 wants to evaluate 40ms bundling, RAN1 specifications may support this case by assuming 15kHz SCS (single and multi-tone) in the uplink. It is up to SA4 whether to consider this case in their evaluations.

  • RAN1/2 have not yet started the work on designing SPS. Therefore, RAN1 currently cannot confirm whether the example frame structure for SPS (related to Figure 5.2.2.3-2 and associated text) will be supported.

  • In previous RAN1 evaluations related to voice, RAN1 has considered 2% BLER as the target performance metric. It is up to SA4 to decide what values to use in their evaluations.

  • Power classes are to be confirmed by RAN4.

  • Although the example Figure 5.2.2.3-1 is supportable by RAN1 specifications in most scenarios, it may not be supportable in the case where the cell is very large (e.g. >3000km), when the UE does not support TA report and the network does not support UE-specific K-offset. The example Figure 5.2.2.3-1 itself also requires the UE to be configured with two HARQ processes and with HARQ feedback disabled.

Proposal 2: RAN1 considers that the value of -31.6dB/K may be used by SA4 in their evaluations. Some companies in RAN1 consider that values higher than -31.6dB/K can be supported in commercial implementations, but RAN1 could not reach consensus on these values.

Document Information
Source:
RAN1
Type:
LS in
For:
Discussion
Original Document:
View on 3GPP
Title: Reply LS on the RAN simulation assumptions for ULBC
Agenda item: 5.2
Agenda item description: Other 3GPP groups
Doc type: LS in
For action: Discussion
Release: Rel-20
Original LS: R1-2506541
Cc: RAN4, RAN2, SA2, CT1
To: SA4
Contact: Andrijana Brekalo
Uploaded: 2026-01-21T08:41:10.920000
Contact ID: 91743
TDoc Status: noted
Reservation date: 21/01/2026 08:29:54
Agenda item sort order: 7