專利摘要：
A method of side-link transmission for ultra-reliable and low latency communication (URLLC), for a first user equipment (UE) of a wireless communication system is disclosed. The method comprises receiving a radio resource control, RRC, signaling for a first resource configuration, from a second UE of the side-link communication, wherein the second UE receives a grant-free uplink resource reserved for a grant-free uplink transmission, from a base station the wireless communication system, and transmitting a first RRC signal for a second resource configuration, to the second UE when the first resource configuration cannot support requirements of URLLC transmission.