对认知无线电波束成形算法的探讨

对多天线协作双向认知无线电系统中的波束成形算法进行了研究。在多天线协作双向认知无线电系统中,2个主用户系统通过次用户进行信息交换,次用户配置多个天线,且次用户通过叠加信号后将其发送给主用户,所以对分配发送主用户和次用户信息的信号的功率以及设计主用户和次用户的波束成形矩阵等进行了重点研究。依据最大化系统容量的优化准则,得到的优化问题均是非凸问题,因此采用半正定优化和二阶圆锥优化,得到闭合解。仿真结果表明,此方法优于以往的波束成形算法。

Study of Beam-forming Algorithm in Two-way Multi-antenna Cognitive Radio System

The beam-forming algorithm in two-way multi-antenna collaborative cognitive radio system is studied. In this system, primary user systems exchange information through the secondary users, while the secondary user has multiple antennas and will send superimposed signals to the primary user. The key issue of this study is how to distribute the power of sending the primary user information and the power of of sending the secondary user information ;how to design the primary user beam-forming matrix ; and how to design a beam-forming matrix of secondary users. In this paper, the optimization criterion of maximizing system capacity is proposed, and the resulting non-convex optimization is obtained. The semi-definite optimization and second-order cone optimization are used, and result is in the closed form. The simulation shows that this method is superior to conventional beam-forming algorithms.