IP Library › Granted Patent US 12701610
Granted Patent B2
US 12701610 · App. 17/999,350 · Granted Aug 4, 2026

Subchannel-based listen before talk for unlicensed channel access

Inventors: Stelios Stefanatos (San Diego, CA); Shuanshuan Wu (San Diego, CA); Peter Gaal (San Diego, CA); Xiaoxia Zhang (San Diego, CA); Tao Luo (San Diego, CA); Arthur Gubeskys (San Diego, CA); Jing Sun (San Diego, CA); Juan Montojo (San Diego, CA)
Assignee: QUALCOMM Incorporated
H04W74/0808
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Quick Facts
Patent No.
US 12701610
App. No.
17/999,350
Granted
Aug 4, 2026
Kind
B2
Abstract

Certain aspects of the present disclosure provide techniques for subchannel-based listen before talk (LBT). An example method that may be performed by a user equipment (UE) includes receiving one or more transmissions indicating one or more allocated subchannels of a frequency band that are allocated during a first time period, the frequency band comprising the one or more allocated subchannels and one or more unallocated subchannels during the first time period; sensing the one or more unallocated subchannels for at least a portion of the first time period prior to a second time period; and transmitting a signal within the frequency band during the second time period based on energy sensed for the one or more unallocated subchannels being less than a threshold.

Claims (48)

1 . An apparatus for wireless communications at a user equipment (UE), the apparatus comprising:

one or more memories; and

one or more processors coupled with the one or more memories and configured to cause the UE to:

receive one or more transmissions that indicate one or more allocated subchannels of a frequency band that are allocated during a first time period, the frequency band comprising the one or more allocated subchannels and one or more unallocated subchannels during the first time period;

sense only the one or more unallocated subchannels for at least a portion of the first time period prior to a second time period; and

transmit a signal within the frequency band during the second time period based on a determination that energy sensed for the one or more unallocated subchannels is less than a threshold.

2 . The apparatus of claim 1 , wherein the threshold is based on a ratio of a first bandwidth of the one or more unallocated subchannels to a second bandwidth of the frequency band.

3 . The apparatus of claim 1 , wherein to cause the UE to sense only the one or more unallocated subchannels, the one or more processors are configured to cause the UE to exclude sensing of one or more frequency subbands, within the one or more unallocated subchannels, that are adjacent to the one or more allocated subchannels.

4 . The apparatus of claim 3 , wherein the threshold is based on a ratio of a first bandwidth of the one or more unallocated subchannels excluding the one or more frequency subbands to a second bandwidth of the frequency band.

5 . The apparatus of claim 3 , wherein a bandwidth of each of the one or more frequency subbands is fixed.

6 . The apparatus of claim 3 , wherein for each of the one or more frequency subbands, a corresponding bandwidth of a corresponding frequency subband is based on a corresponding signal strength of a corresponding signal received on a corresponding allocated subchannel adjacent to the corresponding frequency subband.

7 . The apparatus of claim 3 , wherein for each of the one or more frequency subbands, a corresponding bandwidth of a corresponding frequency subband is based on a corresponding distance between the UE and a corresponding device allocated a corresponding allocated subchannel adjacent to the corresponding frequency subband.

8 . The apparatus of claim 1 , wherein the one or more processors are further configured to cause the UE to:

apply a filter bank to an input signal corresponding to the frequency band, the filter bank configured to filter the one or more allocated subchannels from the input signal, and

sense the input signal after the filter bank is applied.

9 . The apparatus of claim 1 , wherein the first time period and the second time period each comprises a slot.

10 . The apparatus of claim 1 , wherein a channel occupancy time (COT) includes the first time period and the second time period.

11 . The apparatus of claim 1 , wherein the one or more processors are configured to cause the UE to transmit the signal via a sidelink channel.

12 . The apparatus of claim 11 , wherein the UE comprises a cellular vehicle-to-everything (CV2X) device.

13 . The apparatus of claim 1 , wherein the frequency band comprises an unlicensed band.

14 . A method for wireless communications performed by a user equipment (UE), the method comprising:

receiving one or more transmissions indicating one or more allocated subchannels of a frequency band that are allocated during a first time period, the frequency band comprising the one or more allocated subchannels and one or more unallocated subchannels during the first time period;

sensing only the one or more unallocated subchannels for at least a portion of the first time period prior to a second time period; and

transmitting a signal within the frequency band during the second time period based on energy sensed for the one or more unallocated subchannels being less than a threshold.

15 . The method of claim 14 , wherein the threshold is based on a ratio of a first bandwidth of the one or more unallocated subchannels to a second bandwidth of the frequency band.

16 . The method of claim 14 , wherein sensing only the one or more unallocated subchannels comprises sensing the one or more unallocated subchannels excluding sensing of one or more frequency subbands, within the one or more unallocated subchannels, that are adjacent to the one or more allocated subchannels.

17 . The method of claim 16 , wherein the threshold is based on a ratio of a first bandwidth of the one or more unallocated subchannels excluding the one or more frequency subbands to a second bandwidth of the frequency band.

18 . The method of claim 16 , wherein a bandwidth of each of the one or more frequency subbands is fixed.

19 . The method of claim 16 , wherein for each of the one or more frequency subbands, a corresponding bandwidth of a corresponding frequency subband is based on a corresponding signal strength of a corresponding signal received on a corresponding allocated subchannel adjacent to the corresponding frequency subband.

20 . The method of claim 16 , wherein for each of the one or more frequency subbands, a corresponding bandwidth of a corresponding frequency subband is based on a corresponding distance between the UE and a corresponding device allocated a corresponding allocated subchannel adjacent to the corresponding frequency subband.

21 . The method of claim 14 , wherein the sensing comprises:

applying a filter bank to an input signal corresponding to the frequency band, the filter bank configured to filter the one or more allocated subchannels from the input signal; and

sensing the input signal after applying the filter bank.

22 . The method of claim 14 , wherein the first time period and the second time period each comprises a slot.

23 . The method of claim 14 , wherein a channel occupancy time (COT) includes the first time period and the second time period.

24 . The method of claim 14 , wherein transmitting the signal is via a sidelink channel.

25 . The method of claim 24 , wherein the UE comprises a cellular vehicle-to-everything (CV2X) device.

26 . The method of claim 14 , wherein the frequency band comprises an unlicensed band.

27 . An apparatus for wireless communications, the apparatus comprising:

means for receiving one or more transmissions indicating one or more allocated subchannels of a frequency band that are allocated during a first time period, the frequency band comprising the one or more allocated subchannels and one or more unallocated subchannels during the first time period;

means for sensing only the one or more unallocated subchannels for at least a portion of the first time period prior to a second time period; and

means for transmitting a signal within the frequency band during the second time period based on energy sensed for the one or more unallocated subchannels being less than a threshold.

28 . The apparatus of claim 27 , wherein the threshold is based on a ratio of a first bandwidth of the one or more unallocated subchannels to a second bandwidth of the frequency band.

29 . A non-transitory computer-readable storage medium having instructions stored thereon that, when executed by an apparatus, cause the apparatus to perform operations including:

receiving one or more transmissions indicating one or more allocated subchannels of a frequency band that are allocated during a first time period, the frequency band comprising the one or more allocated subchannels and one or more unallocated subchannels during the first time period;

sensing only the one or more unallocated subchannels for at least a portion of the first time period prior to a second time period; and

transmitting a signal within the frequency band during the second time period based on energy sensed for the one or more unallocated subchannels being less than a threshold.

30 . The non-transitory computer-readable storage medium of claim 29 , wherein the threshold is based on a ratio of a first bandwidth of the one or more unallocated subchannels to a second bandwidth of the frequency band.