一种基于两级预编码的认知MIMO系统干扰抑制算法

摘要

In the cognitive radio system,both the interference to primary users and among cognitive users must be effectively suppressed.Thus,an interference suppression scheme for cognitive radio system based on two-level precoding is proposed.First,the subspace orthogonal projection theory is adopted to project the transmitted signal of cognitive users onto the null-space of interference channel in order to eliminating the interference to the primary users.Then,precoding based on signal-to-leakage-and-noise ratio (SLNR) is used to minimize the interference among cognitive users and to improve the cognitive system performance.Simulation results show that,in addition to not affecting the primary users,the method proposed can effectively improve the BER performance and capability of the system and make a well tradeoff between system efficiency and reliability by choosing appropriate substreams amount.%在认知无线电系统中,认知用户通信必须同时解决对主用户造成的干扰和认知用户间的相互干扰问题.为此,提出一种基于两级预编码的认知MIMO系统干扰抑制算法,首先利用子空间正交投影理论,将认知用户的发射信号投影到干扰信道的零空间来消除主用户干扰,然后用信漏噪比预编码最小化认知用户间干扰,提高认知系统性能.仿真结果表明,在不影响主用户的前提下,该算法有效提高了系统误码率性能及其容量,并可以通过选择合适的子流数目,达到系统有效性和可靠性的良好折中.