Dispersed Signal Transmission and Reception Scheme for Full-Duplex Systems

A dispersed signal transmission and reception scheme is proposed to cope with self-interference (SI) and inter-user interference (IUI) in full-duplex systems. During transmission, each identical signal of each transmitter is transmitted in multiple time slots after being multiplied by the transmission coefficients corresponding to the individual time slots. During reception, each receiver multiplies the corresponding reception coefficient by the signal received in each time slot and combines all of the signals received during all of the time slots. To cope with SI and IUI, it is shown that the orthogonality conditions between the transmission and reception coefficients should be satisfied in the transmission and reception procedures. The proposed scheme can be operated without knowledge of both the channel state information and signals of the IUI, and without conventional digital SI cancellation procedures. Simulation results show that the proposed scheme has better achievable rates and bit error rates for both downlink and uplink transmissions than conventional full-duplex systems when the signal-to-noise ratios of the desired signal are low, severe interference exists, and the number of users increases.