An integrated circuit includes control circuitry, which, in operation, controls: i) in a first case that a relation between a first resource pool in a first carrier and a priority of a packet satisfies a determined condition, selecting the first resource pool for transmission of the packet; and transmitting the packet using the first resource pool, and ii) in a second case that the relation between the first resource pool in the first carrier and the priority of the packet does not satisfy the determined condition, selecting a second resource pool out of a plurality of resource pools in a plurality of carriers, based on channel busy ratios (CBRs) of the plurality of resource pools, wherein the second resource pool is selected in increasing order of the CBRs from a lowest CBR of the CBRs; and transmitting the packet using the second resource pool.