Mechanism for sharing channel occupancy time
According to embodiments of the present disclosure, a first device determines one or more second devices to share a channel occupancy time (COT) for a sidelink transmission over an unlicensed spectrum bands. The first device transmits the information which indicates the COT to be shared by the first device and the one or more second devices. The second device determines a transmission gap within the COT and performs a LBT/CCA on the unlicensed spectrum bands based on the determined gap. In this way, it achieves sharing the COT among SL devices. It can improve spectrum efficiency and avoid resource waste.
1 . A first device comprising:
at least one processor; and
at least one memory storing instructions that, when executed by the at least one processor, cause the first device at least to perform:
determining one or more second devices to share a channel occupancy time for a sidelink transmission over an unlicensed spectrum band;
transmitting information indicating the channel occupancy time to be shared by the first device and the determined one or more second devices;
determining a transmission gap within the channel occupancy time based at least on sidelink transmissions from the determined one or more second devices, wherein determining the transmission gap within the channel occupancy time comprises:
in accordance with a determination that the sidelink control information indicating an identity of the shared channel occupancy time, determining the transmission gap within the channel occupancy time based on the sidelink transmissions;
performing a listen-before-talk on the unlicensed spectrum band based on the determined gap; and
transmitting, to the one or more second devices, sidelink control information indicating the identity of the shared channel occupancy time, wherein the identity of the shared channel occupancy time comprises an identity of the first device, and wherein the sidelink control information is transmitted via sidelink in an unlicensed spectrum (SL-U) transmission.
2 . The first device of claim 1 , wherein determining the one or more second devices comprises:
determining the one or more second devices, in accordance with at least one of conditions:
a congestion level on a further sidelink spectrum band associated with sidelink communication of one or more second devices,
a clear channel assessment or listen-before-talk result in the unlicensed spectrum band,
an expected reference signal received power measured by the one or more second devices,
a quality of service of sidelink communication of the first device, or
a logical relationship with the first device.
3 . The first device of claim 1 , wherein transmitting the information indicating channel occupancy time to be shared by one or more second devices comprises:
transmitting the information via a sidelink groupcast; and
wherein determining the transmission gap within the channel occupancy time comprises:
in accordance with a determination that the sidelink transmissions are associated with the sidelink groupcast, determining the transmission gap within the channel occupancy time based on the sidelink transmissions.
4 . The first device of claim 1 , wherein the first device is further caused to perform:
performing a measurement on other sidelink transmissions from a third device which is different from the determined one or more second devices;
wherein determining the transmission gap within the channel occupancy time comprises:
in accordance with a determination that a measurement result on the other sidelink transmissions exceeds a threshold, determining the transmission gap based on the sidelink transmissions and the other sidelink transmissions.
5 . The first device of claim 4 , wherein the measurement on the other sidelink transmissions comprises at least one of:
a measurement of reference signal received power of the other sidelink transmission from the third device; or
a measurement of distance between the third device and the first device.
6 . The first device of claim 1 , the first device is further caused to perform:
determining energy of sidelink transmissions on the sidelink on the unlicensed spectrum band; and
determining result of a listen-before-talk on the unlicensed spectrum band in accordance with a difference between the energy and a measured energy of the listen-before-talk.
7 . The first device of claim 1 , wherein the first device is a terminal device or a network device, and the second device is another terminal device or another network device.
8 . A second device comprising:
at least one processor; and
at least one memory storing instructions that, when executed by the at least one processor, cause the second device at least to perform:
receiving, at a second device and from a first device, information indicating channel occupancy time to be shared by the first device and the second device;
determining a transmission gap within the channel occupancy time based at least in part on sidelink transmissions from the first device, wherein determining the transmission gap within the channel occupancy time comprises:
in accordance with a determination that the sidelink control information indicating the identity of the shared channel occupancy time, determining the transmission gap within the channel occupancy time based on the sidelink transmissions;
performing a listen-before-talk on the unlicensed spectrum band based on the determined transmission gap; and
receiving, from the first device, sidelink control information indicating an identity of the shared channel occupancy time, wherein the identity of the shared channel occupancy time comprises an identity of the first device, and wherein the sidelink control information is transmitted via sidelink in an unlicensed spectrum (SL-U) transmission.
9 . The second device of claim 8 , wherein receiving the information indicating channel occupancy time to be shared by one or more second devices comprises:
receiving the information via a sidelink groupcast; and
wherein determining the transmission gap within the channel occupancy time comprises:
in accordance with a determination that the sidelink transmissions are associated with the sidelink groupcast, determining the transmission gap within the channel occupancy time based on the sidelink transmissions.
10 . The second device of claim 8 , wherein the second device is further caused to perform:
performing a measurement on other sidelink transmissions from a third device which is different from the first device;
wherein determining the transmission gap within the channel occupancy time comprises:
in accordance with a determination that a measurement result on the other sidelink transmissions exceeds a threshold, determining the transmission gap based on the sidelink transmissions and the other sidelink transmissions.
11 . The second device of claim 10 , wherein the measurement on the other sidelink transmissions comprises at least one of:
a measurement of reference signal received power of the other sidelink transmission from the third device; or
a measurement of distance between the third device and the second device.
12 . The second device of claim 8 , wherein the second device is further caused to perform:
determining energy of sidelink transmissions on the sidelink on the unlicensed spectrum band; and
determining result of a listen-before-talk on the unlicensed spectrum band in accordance with a determination of a difference between the energy and a measured energy of the listen-before-talk.
13 . The second device of claim 8 , wherein the first device is a terminal device or a network device, and the second device is another terminal device or another network device.
14 . A method, comprising:
determining, at a first device, one or more second devices to share a channel occupancy time for a sidelink transmission over an unlicensed spectrum band;
transmitting, at the first device, information indicating the channel occupancy time to be shared by the first device and the determined one or more second devices;
determining a transmission gap within the channel occupancy time based at least on sidelink transmissions from the determined one or more second devices, wherein determining the transmission gap within the channel occupancy time comprises:
in accordance with a determination that the sidelink control information indicating an identity of the shared channel occupancy time, determining the transmission gap within the channel occupancy time based on the sidelink transmissions;
performing a listen-before-talk on the unlicensed spectrum band based on the determined gap; and
transmitting, to the one or more second devices, sidelink control information indicating the identity of the shared channel occupancy time, wherein the identity of the shared channel occupancy time comprises an identity of the first device, and wherein the sidelink control information is transmitted via sidelink in an unlicensed spectrum (SL-U) transmission.
15 . The method of claim 14 , wherein transmitting the information indicating channel occupancy time to be shared by one or more second devices comprises:
transmitting the information via a sidelink groupcast; and
wherein determining the transmission gap within the channel occupancy time comprises:
in accordance with a determination that the sidelink transmissions are associated with the sidelink groupcast, determining the transmission gap within the channel occupancy time based on the sidelink transmissions.