Method and apparatus for performing user equipment autonomous resource reselection based on counter in wireless communication system
In a wireless communication system, a user equipment (UE) may reselect a sidelink resource to be used for vehicle-to-everything (V2X) communication. The reselection of sidelink resource may be triggered by various conditions. In particular, the reselection of the sidelink resources may be triggered when a value of sidelink resource reselection counter is zero. More specifically, the UE determines that data for the V2X communication is available in a sidelink traffic channel (STCH), determines that a value of the sidelink resource reselection counter is zero, and reselects the sidelink resources.
1. A method for reselecting a sidelink resource by a user equipment (UE) in a wireless communication system, the method comprising:
determining, by the UE, that data for vehicle-to-everything (V2X) communication is available in a sidelink traffic channel (STCH);
determining, by the UE, that a value of sidelink resource reselection counter is zero;
reselecting the sidelink resource by the UE; and
transmitting, by the UE, the data based on the sidelink resource,
wherein the value of the sidelink resource reselection counter is decreased by 1 when a hybrid automatic repeat request (HARQ) transmission of the data is completed.
2. The method of claim 1 , further comprising:
randomly selecting a value between 5 and 15 with equal probability for the sidelink resource reselection counter; and
setting the value of the sidelink resource reselection counter to the selected value.
3. The method of claim 1 , further comprising:
determining a number of HARQ retransmissions within a range configured by an upper layer.
4. The method of claim 1 , further comprising:
determining an amount of frequency resources within a range configured by an upper layer.
5. The method of claim 1 , wherein the reselecting the sidelink resource comprises:
randomly selecting time and frequency resources from a resource pool indicated from a physical layer.
6. The method of claim 5 , wherein the resource pool indicated from the physical layer does not include resources excluded by the physical layer according to a delay requirement of the V2X communication.
7. The method of claim 6 , wherein the resources excluded by the physical layer are determined according to a maximum allowed physical sidelink shared channel (PSSCH) transmission time.
8. The method of claim 1 , wherein the sidelink resource reselection is performed for each sidelink logical channel.
9. A user equipment (UE) in a wireless communication system, the UE comprising:
a memory;
a transceiver; and
a processor, coupled to the memory and the transceiver, and configured to:
determine that data for vehicle-to-everything (V2X) communication is available in a sidelink traffic channel (STCH),
determine that a value of sidelink resource reselection counter is zero,
reselect the sidelink resource, and
control the transceiver to transmitting the data based on the sidelink resource,
wherein the value of the sidelink resource reselection counter is decreased by 1 when a hybrid automatic repeat request (HARQ) transmission of the data is completed.
10. The UE of claim 9 , wherein the processor further:
randomly selects a value between 5 and 15 with equal probability for the sidelink resource reselection counter; and
sets the value of the sidelink resource reselection counter to the selected value.
11. The UE of claim 9 , wherein the processor further:
determines a number of HARQ retransmissions within a range configured by an upper layer.
12. The UE of claim 9 , wherein the processor further:
determines an amount of frequency resources within a range configured by an upper layer.
13. The UE of claim 9 , wherein the reselecting the sidelink resource comprises:
randomly selecting time and frequency resources from a resource pool indicated from a physical layer.
14. A processor for a wireless communication device in a wireless communication system, wherein the processor is configured to:
determine that data for vehicle-to-everything (V2X) communication is available in a sidelink traffic channel (STCH),
determine that a value of sidelink resource reselection counter is zero, and
reselect the sidelink resource,
control the wireless communication device to transmitting the data based on the sidelink resource,
wherein the value of the sidelink resource reselection counter is decreased by 1 when a hybrid automatic repeat request (HARQ) transmission of the data is completed.