非对称双向中继X网络中基于最大化和速率的干扰对齐与中继处理算法

双向中继X网络相对于传统无线通信网络可以实现更高的自由度.然而,基于迫零算法的中继处理算法仅考虑了消除干扰成分,忽略了对期望信号的影响,从而使得网络的和速率有待提高.特别地,当用户发送功率越低,其和速率劣势越明显.针对上述问题研究其干扰对齐方案,并给出了优化的联合考虑期望信号和干扰信号的中继处理算法.首先,通过利用用户矢量信号之间的空间关系,给出网络和速率的数学模型;其次,通过矩阵分析及数值分析理论将最大化网络和速率的中继预编码设计问题转化为线性搜索最优值问题,并用极限值方法近似网络目标函数;再次,进一步将双向网络的目标函数近似为单向网络用户参数的线性组合,大大降低算法复杂度;最后,基于优化的线性搜索最优值问题,得到最大化网络和速率的中继预编码矩阵.仿真结果表明:相较于现有的中继处理方案,本文方案明显改善了网络和速率,同时还简化了最大化网络和速率带来的算法复杂度.

Interference alignment and relay processing algorithm via sum rate maximization for asymmetric two-way relay X networks

Two-way relay X networks offer a higher degrees of freedom, in contrast to traditional wireless communication networks. The relay processing based on zero forcing only considers the interference, ignoring the desired signal, so that the sum rate of the network to be improved. Specifically, the lower user transmission power, the greater disadvantages. The interference alignment scheme was researched for asymmetric two-way relaying X networks, moreover the relay beamforming technique based on the desired signal and interference signal was also presented. Firstly, a mathematical model was obtained for the network sum rate by the spatial relationship between user signal vectors. Then, the relay beamforming scheme based on sum rate maximization was transformed into a linear search for the optimal value through the matrix analysis and numerical analysis theory, and the objective function of the network was approximated by the limitation. Furthermore, the objective function was approximated by the linear combinations of parameters of oneway network. Finally, the relay precoder matrix to maximize the sum rate was obtained. Simulation results show that the proposed scheme significantly improved the network rate compared with existing relay processing scheme, while simplifying the complexity of the algorithm.