An user equipment supporting Semi-Persistent Scheduling (SPS), the user equipment including: a receiver configure to receive sidelink (SL) SPS radio network temporary identifier (RNTI) from a base station; and receive a SL grant including downlink control information (DCI from the base station with a Physical Downlink Control Channel (PDCCH), wherein the DCI comprises a SL SPS index field and an activation/release indication field if the DCI with Cyclic Redundancy Check (CRC) is scrambled with the SL SPS RNTI, wherein a start subframe for Sidelink Control (SC) period is determined based on an offset value and a subframe in which the sidelink grant is received, and wherein an index of a subframe for SC period is relative to System Frame Number (SFN) 0.