| 主权项 |
1. A method of transmitting a synchronization channel by a terminal in a direct communication between terminals, the method comprising:
using uplink (UL) subframes of a superframe as dedicated resources for the direct communication, the superframe including a plurality of infra communication frames, each infra communication frame including a plurality of subframes, each subframe including a plurality of orthogonal frequency division multiple access (OFDMA) symbols, a part of the plurality of subframes being downlink (DL) subframes and a remaining part of the plurality of subframes being the UL subframes, the dedicated resources forming a direct communication frame including a plurality of subframes, the direct communication frame including a synchronization channel, a plurality of dedicated channels and a plurality of supplementary channels, the synchronization channel being used for a distributed synchronization, the plurality of dedicated channels to send direct communication packets for terminals, the plurality of supplementary channels corresponding to the plurality of dedicated channels, wherein when a terminal receives the dedicated channel after transmitting the synchronization channel or transmits the dedicated channel after receiving the synchronization channel, a transmission-to-reception or reception-to-transmission transition time is required between the synchronization channel and the dedicated channel; transmitting a synchronization channel message part including synchronization information; transmitting a synchronization channel preamble part after transmitting the synchronization channel message part, the synchronization channel preamble part being used for estimating time and frequency synchronization; and receiving a dedicated channel including a direct communication packet after transmitting the synchronization channel preamble part, the dedicated channel being dedicated for the direct communication between terminals and the dedicated channel being adjacent to the synchronization channel preamble part; wherein a transition time gap for the required transmission-to-reception or reception-to-transmission transition time is inserted to an end of the synchronization channel preamble part and within a first subframe of a plurality of subframes, the first subframe including the synchronization channel message part and the synchronization channel preamble part. |
