Apparatus and method for transmitting device to device communication channel in wireless communication system

A user equipment (UE) to perform a device-to-device (D2D) communication with another UE, the UE comprising:

• a processor configured to
• discover the another UE with a discovery signal transmitted in Physical Sidelink Discovery Channel (PSDCH);
• synchronize with the another UE with a synchronization signal including a primary synchronizing signal and a secondary synchronizing signal;
• determine D2D frames available for the D2D communication from an available D2D resource pool, wherein each of the D2D frames consists of 10 D2D subframes, and wherein each of the D2D subframes consists of two D2D slots;
• initialize a pseudo-random sequence for the D2D communication with an initialization value associated with at least one of a group hopping for a demodulation reference signal (DM-RS) on a physical sidelink shared channel (PSSCH) at a D2D slot of number 0 in each of the D2D frames;
• and
• initialize an initialization value associated with a scrambling of a codeword associated with a transmission of a PSSCH at a start of each of the D2D subframes;
• and
• a radio frequency signal transmitter to transceive a D2D signal associated with the pseudo-random sequence,
• wherein the D2D frames are frames in which a PSSCH is transmitted or received,
• wherein the primary synchronizing signal is transmitted in first two Single Carrier-FDMA (SC-FDMA) symbols and the secondary synchronizing signal is transmitted in second two SC-FDMA symbols,
• wherein the first two SC-FDMA symbols are transmitted in a same D2D subframe and the second two SC-FDMA symbols are transmitted in a same D2D subframe.