MIMO-OFDM双向多中继选择的网络资源优化

为加强多输入多输出-正交频分复用(multiple-input multiple-output orthogonal frequency division multiplexing,MIMO-OFDM)双向中继系统的频域和空间复用增益,研究放大转发(amplify-forward,AF)协议下的中继系统模式,提出一种双向信道的预编码矩阵,能够将复杂的双向MIMO-OFDM信道划分为多个独立的物理层网络编码(physical network coding,PNC)子信道.在此基础上,将系统扩展至多中继,并提出在已有的频域子载波和空间子信道的最佳配对方案下,以最大化用户接收信号信噪比为准则,为每组配对方案分配合适的中继来改善中继网络的性能.通过联合优化的中继选择策略,单节点功率约束条件以及拉格朗日对偶方法,获取优化的系统资源分配方案.仿真结果证明,所提算法较一般功率分配方法带来的性能增益随着中继的增加,增益幅度随之增加.

Resource optimizing for MIMO-OFDM two-way multi-relay selecting

To enhance frequent and spatial multiplexing gain of multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) system, the Multi-relay system model is studied which operates in a amplify-forward (AF) protocol. For dividing complicate MIMO-OFDM two-way channels into multiple independent physical network coding(PNC) sub-channels, we have proposed two-way precoding matrices. Based on this, the system is extended to the multi-relay model, then the appropriate relay is chosen to the scheme that subcarriers in frequency and sub-channels in space domain pair by the criterion of maximizing the SNR of the receiving signals at users, which can improve the performance of the relay. Joint the optimal relaying selecting, giving each node a constrained total power and Lagrangian dual method, we obtain the optimal system resource allocation. Finally, simulation results are proposed to demonstrate the performance gain of the algorithms compared to the general power allocation and the greater gain when the number of relays is increasing.