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, wherein the processor is configured to: select a plurality of sidelink resources from a sidelink resource pool; and when at least one of the selected plurality of sidelink resources collides with sidelink resources already reserved in advance by another UE, and an observed packet priority level transmitted by the another UE is lower than an observed packet priority level transmitted by the transceiver, contend the at least one of the sidelink resources already reserved in advance from the another UE by indicating, in sidelink control information, SCI, a resource reservation interval colliding with the at least one resource reservation of the another UE and corresponding to a periodicity of data messages to be transmitted; or determine that one or more of the selected plurality of sidelink resources are contended by another UE when the one or more of the selected plurality of sidelink resources collide with sidelink resources indicated in sidelink control information, SCI, transmitted by the another UE, comprising a resource reservation interval of a transmission of the another UE corresponding to a periodicity of data messages to be transmitted, and an observed packet priority level transmitted by the another UE is higher than an observed packet priority level transmitted by the transceiver; and skip transmission in the contended one or more sidelink resources or perform sidelink resource reselection from the sidelink resource pool. a memory; a transceiver; and a processor coupled to the memory and the transceiver, wherein the processor is configured to: select a plurality of sidelink resources from a sidelink resource pool; and when at least one of the selected plurality of sidelink resources collides with sidelink resources already reserved in advance by another UE, and an observed packet priority level transmitted by the another UE is lower than an observed packet priority level transmitted by the transceiver, contend the at least one of the sidelink resources already reserved in advance from the another UE by indicating, in sidelink control information, SCI, a resource reservation interval colliding with the at least one resource reservation of the another UE and corresponding to a periodicity of data messages to be transmitted; or determine that one or more of the selected plurality of sidelink resources are contended by another UE when the one or more of the selected plurality of sidelink resources collide with sidelink resources indicated in sidelink control information, SCI, transmitted by the another UE, comprising a resource reservation interval of a transmission of the another UE corresponding to a periodicity of data messages to be transmitted, and an observed packet priority level transmitted by the another UE is higher than an observed packet priority level transmitted by the transceiver; and skip transmission in the contended one or more sidelink resources or perform sidelink resource reselection from the sidelink resource pool. select a plurality of sidelink resources from a sidelink resource pool; and when at least one of the selected plurality of sidelink resources collides with sidelink resources already reserved in advance by another UE, and an observed packet priority level transmitted by the another UE is lower than an observed packet priority level transmitted by the transceiver, contend the at least one of the sidelink resources already reserved in advance from the another UE by indicating, in sidelink control information, SCI, a resource reservation interval colliding with the at least one resource reservation of the another UE and corresponding to a periodicity of data messages to be transmitted; or determine that one or more of the selected plurality of sidelink resources are contended by another UE when the one or more of the selected plurality of sidelink resources collide with sidelink resources indicated in sidelink control information, SCI, transmitted by the another UE, comprising a resource reservation interval of a transmission of the another UE corresponding to a periodicity of data messages to be transmitted, and an observed packet priority level transmitted by the another UE is higher than an observed packet priority level transmitted by the transceiver; and skip transmission in the contended one or more sidelink resources or perform sidelink resource reselection from the sidelink resource pool.