Abstract: Aiming at the problem of inter-relay interference (IRI) in amplify-and-forward (AF) two-path successive relay (TPSR), a relay interference cancellation scheme based on row-space-mapping is proposed. The new scheme is to encode the source node signals alternately. Thus, the expectation signal and the IRI signal are mapped to the orthogonal subspace that is independent of channel. The perfect elimination of IRI and accumulated noise is realized under the unknown channel, and the effect of the residual self-interference and accumulated noise caused by the non-ideal channel estimation on TPSR’s performance is eliminated. Furthermore, the closed-form expression and the asymptotic expression of the average bit error rate (BER) of the system under different channel estimation errors are derived, and the correctness of the theoretical deduction is verified by simulation. By comparing this scheme with the traditional interference cancellation scheme based on channel estimation, the detection  performance under different estimation errors shows that the new scheme can completely eliminate IRI and accumulated noise and improve the performance of successive relay network effectively.

Key words: successive relay networks, row-space-mapping, inter-relay interference (IRI), interference cancellation