A spectral efficient relay-based transmit diversity technique for SC-FDE without cyclic prefix

This paper proposes a relay-based transmit diversity technique for single carrier frequency-domain equalization (SC-FDE). The proposed system achieves spatial diversity over fading channels in a distribution fashion without cyclic prefix (CP), which increases spectral efficiency of conventional relay-based systems. The destruction of channel cyclicity due to the lack of CP is recovered at the input of relay and destination. In order to obtain spatial diversity, the transmit sequence of relay is efficiently generated in time domain, realizing space-frequency block code (SFBC). Corresponding destination structure using FDE, timing synchronization, and highly accurate channel estimation for the proposed system are also presented. Simulation results show that the proposed system approaches the lower bound of full-CP system.