A method of transmission by a user equipment (UE) in a wireless communication system, the method including receiving, by the UE from a eNB, a physical downlink control channel (PDCCH) which is scrambled with one of a semi-persistent scheduling (SPS) Cell-radio network temporary identifier (RNTI) or a sidelink RNTI, wherein the PDCCH includes a downlink control information (DCI) format 0 including a three bit-field; and transmitting, by the UE, a signal based on the DCI format 0, wherein the three bit-field is related to a cyclic shift DMRS based on that the PDCCH is scrambled with the SPS C-RNTI, and wherein the three bit-field is used as a resource information for a sidelink communication, based on that the PDCCH is scrambled with the sidelink RNTI.