RAN1 #126-bis agrees NR reference for 6GR uplink 1K QAM MCS design

RAN1 is the radio layer 1 working group, whose chair notes record the agreement under modulation agenda item 10.3.2. The chair notes agree to use NR downlink entries "as a reference for design" of the uplink 1K QAM MCS table. Here, 1K QAM means 1024-level quadrature amplitude modulation, and MCS means modulation and coding scheme. That reference applies at least to cyclic-prefix orthogonal frequency-division multiplexing (CP-OFDM). Our reading: the agreement sets a design reference, not a change to an NR uplink specification.

Source: R1-2607313, Ad-Hoc Chair (Ericsson), 3GPP TSG RAN WG1 #126-bis, chair notes, agenda item 10.3.2.

MediaTek proposed in R1-2607897 studying how much the 5G NR MCS table needs to change and the effect on system complexity. LG Electronics warned in R1-2607450 that a fixed table covering all modulation and coding-rate combinations may significantly increase complexity. Huawei (with HiSilicon) proposed in R1-2607462 considering higher modulation with lower coding rates, or lower modulation with higher coding rates.

CATT said in R1-2607401 that the table might be "extended from 32 entries to 64 entries" for multiple entries at one spectral efficiency. CATT also raised possible control-signaling overhead and changes to the channel-quality table. Our reading: these papers explore table design beyond the agreed reference, rather than opposing that agreement. The document register lists all four contributions as not treated at RAN1 #126-bis, with no decision recorded on them.

Source: R1-2607401, CATT, 3GPP TSG RAN WG1 #126-bis. © CATT.