The Interference Cancellation Scheme for AF Successive Relay Networks Based on Postmultiplying Precoding

To suppress the inter relay interference (IRI) in amplify-and-forward (AF) two-path-successive relay (TPSR), a novel interference cancellation scheme is proposed in this paper based on postmultiplying precoding. Two orthogonal precoding matrices are alternately utilized to post-multiply the source signal, which is projected onto two channel-independent and orthogonal subspaces. The IRI and accumulated noise can be completely eliminated by decoding and re-encoding operation at the relay node. The effect of the residual IRI and accumulated noise caused by the non-ideal channel estimation on the performance of TPSR is eliminated. Finally, the bit error ratio (BER) curves of this scheme and the traditional channel estimation interference cancellation scheme are compared under different estimation errors to show the performance and robustness of the scheme proposed in this paper.