Performance Analyze Of The Relay Beamforming Based On Cognitive Radio

Nowadays, the scarce of wireless spectrum resource and the growing business demand, are one of the paradoxes of wireless communication industry that can be irreconcilable. Cognitive radio is based on.the software-defined radio, with the surrounding environment perception and self-learning capability, self-decision-making ability of intelligent wireless communication system. It allows secondary network users to share of spectrum resources with the main network users without interrupting the primary network. This article is based on the study of the cognitive network performance of multi-antenna relay network under the following major content.Firstly, we assume that perfect MIMO (Multiple-Input Multiple-Output) channel and ensure cognitive wireless network users under the normal communication circumstances and minimize the cognitive radio relay power.Secondly, we assume that the non-perfect MIMO channel and ensure cognitive wireless network users to communicate with each other and minimize cognitive radio relay transmission power. Simulation results compare with robust algorithm and non-robust algorithm.Thirdly, we derivate least upper bound of the constraint conditions.The first content use convex optimization theory to analyze. The contents of the second gives two sets of optimization algorithm to process the problem. Firstly we use linear matrix inequality theory and robust optimization method to transform the mathematical problem into semi-definite problem, and then use semi-definite programming theory to analysis. The third content is that using SVD decomposition and EVD decomposition to contain least upper bound of the constraint condition.Simulation results show that the robust beamforming technique in cognitive relay network outperform the non-robust Beamforming.