Channel access procedures in a wireless network
A base station performs channel access procedures for transmission on the plurality of LAA cells comprising a first cell group and a second cell group. The channel access procedures comprising a first channel access procedure of a first cell of the first cell group. The first channel access procedure is dependent on a second channel access procedure of a second cell of the first cell group and is independent of a third channel access procedure of a third cell of the second cell group.
1. A method comprising:
determining, by a base station, to perform listen-before-talk (LBT) procedures on channels operating in a plurality of unlicensed frequency bands, wherein:
the channels are grouped in sets; and
the sets comprise:
a first subset of the channels operating in a same first unlicensed frequency band; and
a second subset of the channels operating in a same second unlicensed frequency band different from the first unlicensed frequency band;
receiving first feedback of a second channel, wherein the second channel is in the first subset;
receiving second feedback of a third channel, wherein the third channel is in the second subset;
determining, for a first channel in the first subset, a size of a contention window, wherein:
the determining is based on the first feedback in response to the second channel being in the first subset of the channels in the same first unlicensed frequency band; and
the determining is not based on the second feedback in response to the third channel not being in the same first unlicensed frequency band; and
transmitting on the first channel in response to an LBT procedure being performed based on the size of the contention window.
2. The method of claim 1 , wherein the LBT procedure is a multi-channel access procedure type B.
3. The method of claim 1 , further comprising performing the LBT procedure for at least a sensing time interval before transmitting on the second channel.
4. The method of claim 1 , further comprising selecting a counter value between two values determined based on the size of the contention window.
5. The method of claim 4 , further comprising increasing the size of the contention window to a next higher value based on the feedback.
6. The method of claim 1 , further comprising selecting the second channel uniformly randomly from the first subset of the channels.
7. The method of claim 1 , wherein the determining the size of the contention window is not based on the second feedback of the third channel in response to the third channel being in the second subset of the channels.
8. A base station comprising:
one or more processors; and
memory storing instructions that, when executed by the one or more processors, cause the base station to:
determine to perform listen-before-talk (LBT) procedures on channels operating in a plurality of unlicensed frequency bands, wherein:
the channels are grouped in sets; and
the sets comprise:
a first subset of the channels operating in a same first unlicensed frequency band; and
a second subset of the channels operating in a same second unlicensed frequency band different from the first unlicensed frequency band;
receive first feedback of a second channel, wherein the second channel is in the first subset;
receive second feedback of a third channel, wherein the third channel is in the second subset;
determine, for a first channel in the first subset, a size of a contention window, wherein:
the determining is based on the first feedback in response to the second channel being in the first subset of the channels in the same first unlicensed frequency band; and
the determining is not based on the second feedback in response to the third channel not being in the same first unlicensed frequency band; and
transmit on the first channel in response to an LBT procedure being performed based on the size of the contention window.
9. The base station of claim 8 , wherein the LBT procedure is a multi-channel access procedure type B.
10. The base station of claim 8 , wherein the instructions further cause the base station to perform the LBT procedure for at least a sensing time interval before transmitting on the second channel.
11. The base station of claim 8 , wherein the instructions further cause the base station to select a counter value between two values determined based on the size of the contention window.
12. The base station of claim 11 , wherein the instructions further cause the base station to increase the size of the contention window to a next higher value based on the feedback.
13. The base station of claim 8 , wherein the instructions further cause the base station to select the second channel uniformly randomly from the first subset of the channels.
14. The base station of claim 8 , wherein the determining the size of the contention window is not based on the second feedback of the third channel in response to the third channel being in the second subset of the channels.
15. A non-transitory computer-readable medium comprising instructions that, when executed by one or more processors of a base station, cause the base station to:
determine to perform listen-before-talk (LBT) procedures on channels operating in a plurality of unlicensed frequency bands, wherein:
the channels are grouped in sets; and
the sets comprise:
a first subset of the channels operating in a same first unlicensed frequency band; and
a second subset of the channels operating in a same second unlicensed frequency band different from the first unlicensed frequency band;
receive first feedback of a second channel, wherein the second channel is in the first subset;
receive second feedback of a third channel, wherein the third channel is in the second subset;
determine, for a first channel in the first subset, a size of a contention window, wherein:
the determining is based on the first feedback in response to the second channel being in the first subset of the channels in the same first unlicensed frequency band; and
the determining is not based on the second feedback in response to the third channel not being in the same first unlicensed frequency band; and
transmit on the first channel in response to an LBT procedure being performed based on the size of the contention window.
16. The non-transitory computer-readable medium of claim 15 , wherein the LBT procedure is a multi-channel access procedure type B.
17. The non-transitory computer-readable medium of claim 15 , wherein the instructions further cause the base station to perform the LBT procedure for at least a sensing time interval before transmitting on the second channel.
18. The non-transitory computer-readable medium of claim 15 , wherein the instructions further cause the base station to select a counter value between two values determined based on the size of the contention window.
19. The non-transitory computer-readable medium of claim 18 , wherein the instructions further cause the base station to increase the size of the contention window to a next higher value based on the feedback.
20. The non-transitory computer-readable medium of claim 15 , wherein the instructions further cause the base station to select the second channel uniformly randomly from the first subset of the channels.
21. The non-transitory computer-readable medium of claim 15 , wherein the determining the size of the contention window is not based on the second feedback of the third channel in response to the third channel being in the second subset of the channels.