Rx UE(s) assisted channel access procedure for sidelink operation in unlicensed band
A system and a method are disclosed for determining, by a targeted receiving User Equipment (UE), that a corresponding transmitting UE has a future reserved resource block. The receiving UE may perform a Listen Before Talk (LBT) sensing to identify a time period when an unlicensed channel is unoccupied and can be used by the corresponding transmitting UE for the future reserved sidelink transmission. The receiving UE may transmit a reservation signal for the unlicensed channel to the corresponding transmitting UE, during at least a portion of the time period when the unlicensed channel is unoccupied. Further, the receiving UE may, switch, to a receiving mode prior to or at a reserved slot boundary of the future reserved resource block.
1 . A method comprising:
determining, by a targeted receiving User Equipment (UE), that a corresponding transmitting UE has a future reserved resource block;
performing, by the targeted receiving UE, a Listen Before Talk (LBT) sensing to identify a time period when an unlicensed channel is unoccupied, and can be used by the corresponding transmitting UE for the future reserved sidelink transmission;
transmitting a reservation signal for the unlicensed channel to the corresponding transmitting UE, during at least a portion of the time period when the unlicensed channel is unoccupied; and
prior or at a reserved slot boundary of the future reserved resource block, switching, by the receiving UE, to a receiving mode.
2 . The method of claim 1 , wherein the reservation signal includes a set of control information with a Channel Occupancy Time (COT) sharing indication.
3 . The method of claim 2 , wherein a portion or the whole reservation signal carries the set of control information.
4 . The method of claim 2 , wherein the reservation signal has control information in a subset of the reserved channel based on a resource pool (pre)-configuration.
5 . The method of claim 2 , wherein the set of control information is carried in a Demodulation Reference Signal (DMRS) sequence.
6 . The method of claim 2 , wherein the set of control information is carried by one or more Zadoff-Chu (ZC) sequences.
7 . The method of claim 2 , wherein the reservation signal has the set of control information in all reserved subchannels.
8 . The method of claim 1 , wherein multiple UE's are synchronized to a synchronization reference UE wherein each of the synchronized UEs perform Listen Before Talk sensing and reserve the channel on behalf of the synchronization reference UE.
9 . The method of claim 1 , further comprising:
performing a sidelink transmission, by the corresponding transmitting UE, at the reserved slot boundary over the reserved resource block.
10 . The method of claim 1 , further comprising, a reservation signal with a duty cycle of less than 100%.
11 . A method comprising:
creating a reservation for a resource block, by a transmitting User Equipment (UE);
receiving a reservation signal on the transmitting UE, transmitted by a receiving UE on an unlicensed channel; and
decoding the reservation signal, by the transmitting UE, wherein the reservation signal was transmitted for the unlicensed channel to the transmitting UE, by the receiving UE, during at least a portion of a time period when the unlicensed channel is unoccupied; and
wherein the receiving UE performed a Listen Before Talk sensing to identify the time period when the unlicensed channel was unoccupied, and the transmitting UE can use the future reserved resource block.
12 . The method of claim 11 , wherein the reservation signal includes a set of control information with a Channel Occupancy Time (COT) sharing indication.
13 . The method of claim 12 , wherein a portion or the whole reservation signal carries the set of control information.
14 . The method of claim 12 , wherein the reservation signal has control information in a subset of the reserved channel based on a resource pool (pre)-configuration.
15 . The method of claim 12 , wherein the set of control information is carried in a Demodulation Reference Signal (DMRS) sequence.
16 . The method of claim 12 , wherein the set of control information is carried by one or more Zadoff-Chu (ZC) sequences.
17 . The method of claim 12 , wherein the reservation signal has the set of control information in all reserved subchannels.
18 . The method of claim 11 , wherein multiple UE's are synchronized to a synchronization reference UE wherein each of the synchronized UEs perform Listen Before Talk sensing and reserve the channel on behalf of the synchronization reference UE.
19 . A device comprising:
a transceiver; and a
processor configured to:
determine, via the transceiver, that a corresponding transmitting User Equipment (UE) has a future reserved resource block;
perform, via the transceiver, a Listen Before Talk (LBT) sensing to identify a time period when an unlicensed channel is unoccupied, and can be used by the corresponding device for the future reserved sidelink transmission;
transmit a reservation signal for the unlicensed channel to the corresponding transmitting UE, during at least a portion of the time period when the unlicensed channel is unoccupied; and
prior or at a reserved slot boundary of the future reserved resource block, switch, by the device, to a receiving mode.
20 . The device of claim 19 , wherein the reservation signal includes a set of control information with a Channel Occupancy Time (COT) sharing indication.