中文摘要：

为了进一步提高认知通信的传输速率，将用户合作通信技术引入认知无线电通信系统．建立了保护主用户的传送不被干扰前提下的认知中继通信模型，并分析了认知中继通信信道的容量．给出了应用认知中继通信的约束条件，并讨论了最佳认知中继伙伴的选择方法，以及多认知中继节点进行空时编码时的最佳功率分配策略．在仿真实验中，给出了在高斯环境下提高认知通信速率的中继节点的可能位置，从而证明了应用认知中继传送信息的可行性．比较了使用认知中继时和直接传输时的速率，结果表明，采用认知中继传送可有效提高认知通信系统容量．

英文摘要：

User cooperation was introduced to the application of cognitive radio to further promote the performance of cognitive transmission. The capacity of cognitive relay channel was computed under the constraint of protecting the primary user from extra interference. The restriction to cognitive relay transmission was analyzed. The method to select the best relay was discussed. The optimal power allocation strategy with space time code adopted in multi-relay scenario was analyzed. The simulation results illustrated the potential locating area of capable relays in Gaussian environment, thereby demonstrated the feasibility of cognitive relay transmission. The comparision between cognitive relay transmission rate and direct cognitive transmission rate shows that the cognitive relay transmission practically promotes the performance of cognitive communication system.