Methods for contention-based sidelink transmission and reception and related wireless devices
Disclosed is a method performed by a wireless transmitter device, for contention-based sidelink transmission. The method comprises obtaining information defining a transmission resource pool and a resource reservation pool comprising one or more reservation resources associated with respective transmission resources in the transmission resource pool. The method comprises monitoring a reservation resource associated with a transmission resource selected by the wireless transmitter device for sidelink transmission, for a resource reservation signal transmitted by one or more other wireless transmitter devices attempting to reserve the same transmission resource. The method comprises: upon determining based on the monitoring that the transmission resource is available, transmitting, after the monitoring, to a wireless device, using the reservation resource, a resource reservation signal indicating that the wireless transmitter device intends to use the transmission resource. The timing of the transmission of the resource reservation signal is randomly selected by the wireless transmitter device.
1. A method, performed by a wireless transmitter device, for contention-based sidelink transmission, the method comprising:
obtaining information defining a transmission resource pool and a resource reservation pool comprising one or more reservation resources associated with respective transmission resources in the transmission resource pool;
monitoring a reservation resource associated with a transmission resource selected by the wireless transmitter device for sidelink transmission, for a resource reservation signal transmitted by one or more other wireless transmitter devices attempting to reserve the same transmission resource; and
upon determining based on the monitoring that the transmission resource is available, transmitting, after the monitoring, to a wireless device, using the reservation resource, a resource reservation signal serving as a Wake-Up Signal (WUS) of the wireless device and indicating to other wireless devices that the wireless transmitter device intends to use the transmission resource;
wherein a timing of the transmission of the resource reservation signal is randomly selected by the wireless transmitter device; and wherein the modulation and coding complexity of the resource reservation signal is lower than a modulation and coding complexity of the sidelink transmission.
2. The method according to claim 1 , wherein the reservation resource signal is a signal requiring less power than the sidelink transmission.
3. The method according to claim 1 , wherein the reservation resource signal comprises a sequence generated based on a predetermined rule and/or a predetermined formula.
4. The method according to claim 1 , wherein a size of a monitoring window where the monitoring is performed is randomly selected by the wireless transmitter device.
5. The method according to claim 1 , wherein the transmission of the resource reservation signal upon determining based on the monitoring that the transmission resource is available is performed immediately after the monitoring.
6. The method according to claim 1 , the resource reservation signal comprises a first part recognizable by any wireless device and a second part dedicated to a target wireless receiver device.
7. The method according to claim 1 , the method comprising randomly selecting the reservation resource amongst pre-configured reservation resources.
8. The method according to claim 1 , wherein the transmission resource is part of one or more of: a Physical Sidelink Control Channel (PSCCH) and/or a Physical Sidelink Shared Channel (PSSCH).
9. The method according to claim 1 , the method comprising performing, the sidelink transmission to the wireless receiver device, using the transmission resource, after the transmission of the resource reservation signal.
10. The method according to claim 1 , wherein the reservation resource is in time prior to the transmission resource of the transmission resource pool.
11. The method according to claim 1 , wherein a size of the reservation resource allows for the monitoring of resource reservation transmitted by other wireless devices and for transmission of the resource reservation signal.
12. The method according to claim 6 , wherein the resource reservation signal transmitted by the wireless transmitter device is indicative of an identifier associated with the target wireless receiver device.
13. The method according to claim 12 , wherein the second part comprises an identifier configured to identify the target wireless receiver device and/or a group of wireless receiver devices to which the target wireless receiver device belongs.
14. The method according to claim 12 , wherein the second part comprising the identifier.
15. The method according to claim 6 , wherein the first part comprises a preamble recognizable by one or more wireless receiver devices.
16. The method according to claim 1 , the method comprising determining whether the reservation resource is available.
17. The method according to claim 16 , wherein the determining comprises determining whether the monitoring satisfies a criterion.
18. The method according to claim 17 , wherein the monitoring satisfies a criterion when a level of the received reservation signal is below a threshold.
19. The method according to claim 17 , wherein the monitoring satisfies a criterion when no reservation signal is detected in.