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Contested proposalRAN1 #126-bis

Agreement on Option 4 D2R bit durations at RAN1 #126-bis

Published 2026-11-13Updated 2026-11-133GPP TSG RAN WG1 #126-bis

At a glance

The radio layer 1 working group (RAN1) agreed Option 4, with shortest bit durations of 1.39 microseconds for Device 2b and 2.78 microseconds for Device C.

Who proposed what

At RAN1 #126-bis, the chair notes record an agreement to "support Option 4 with the following bit duration sets". This Release 20 (Rel-20) work concerns ambient internet of things (IoT) device-to-reader (D2R) transmission for Device 2b and Device C. The agreed Device 2b set is 266.67, 133.33, 66.67, 33.33, 16.67, 8.33, 4.17 and 1.39 microseconds. The Device C set is 266.67, 133.33, 66.67, 33.33, 16.67, 8.33, 4.17 and 2.78 microseconds.

Source: R1-2607286, Ad-Hoc Chair (NTT DOCOMO, INC.), 3GPP TSG RAN WG1 #126-bis, chair notes, agenda item 9.3.2.

NTT DOCOMO proposed "support option 3 as first priority and option 4 as 2nd priority". Apple preferred Option 3 for both device types, with the set ending at 2.78 microseconds. ZTE (with Sanechips) proposed a set ending at 2.78 microseconds for Rel-20 D2R transmission, without naming device types or Option 3.

Source: R1-2608331, NTT DOCOMO, 3GPP TSG RAN WG1 #126-bis. © NTT DOCOMO.

IIT Kharagpur (with IISc, Tejas Networks, Reliance Jio) proposed Option 4 with separate sets for the two device types. They identified the Device 2b set as the Release 19 (Rel-19) set, with 1.39 microseconds as its shortest duration. For Device C, they proposed a "coverage-oriented set without the shortest bit duration", ending at 2.78 microseconds.

Source: R1-2608609, IIT Kharagpur (with IISc, Tejas Networks, Reliance Jio), 3GPP TSG RAN WG1 #126-bis. © IIT Kharagpur, IISc, Tejas Networks, Reliance Jio.

Sources

  1. R1-2607286, Ad-Hoc Chair (NTT DOCOMO, INC.), 3GPP TSG RAN WG1 #126-bis, chair notes, agenda item 9.3.2.
  2. R1-2608207, Apple, 3GPP TSG RAN WG1 #126-bis. © Apple.
  3. R1-2608331, NTT DOCOMO, 3GPP TSG RAN WG1 #126-bis. © NTT DOCOMO.
  4. R1-2607375, ZTE (with Sanechips), 3GPP TSG RAN WG1 #126-bis. © ZTE, Sanechips.
  5. R1-2608609, IIT Kharagpur (with IISc, Tejas Networks, Reliance Jio), 3GPP TSG RAN WG1 #126-bis. © IIT Kharagpur, IISc, Tejas Networks, Reliance Jio.

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