基于行空间映射的连续中继网络预编码干扰消除方案

针对转发放大(amplify-and-forward,AF)模式下双路径连续中继(two-path successive relay,TPSR)存在的中继间干扰(inter-relay interference,IRI)问题,提出了新颖的基于行空间映射的中继干扰消除方案。新方案对源节点信号进行交替行空间预编码,从而将接收期望信号与IRI信号映射到不依赖信道的正交子空间,在未知信道下实现IRI和累计噪声的完美消除,从而消除非理想信道估计带来的剩余自干扰和累积噪声对TPSR性能的影响。在这基础上,推导不同信道估计误差下系统平均误比特率(bit error ratio,BER)的闭合表达式和近似表达式,并通过仿真验证理论推导的正确性。通过对比该方案与传统基于信道估计的干扰消除方案在不同估计误差下的检测性能,表明新方案能够完全消除IRI和累积噪声,有效提升连续中继网络性能。

Precoding interference cancellation scheme for successive relay networks based on row-space-mapping

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.