中文摘要：

提出了一种多主从用户相互协作的认知共存网络系统模型.在该模型中,控制中心已知所有用户的位置并为每个主用户分配最近的从用户进行协作通信,控制中心通过从用户反馈的感知结果来获取频谱空洞信息并为从用户分配工作频段.主用户利用正交子信道接入基站.从用户利用网络中未用的频谱空洞采用放大前传机制为主用户转发数据.推导了在该模型下主用户的中断概率,并对主用户发送概率ps、主从用户间发射功率分配系数ξ和主从用户数对系统的影响进行了仿真.仿真结果表明,主从用户间平均分配发射功率在ξ=0.5且网络中主从用户数目相同时系统性能最优.

英文摘要：

A cooperative model of multiple primary and secondary users coexisting cognitive network is presented. In this model, the control center is aware of all the users＇ locations in order to allocate the nearest secondary user to the primary user. The control center is aware of the information of the unused spectral resources in terms of the feedback of the sensing results from the secondary users. It allocates idle frequency bands among the secondary users. The primary user accesses the base station （BS） in orthogonal subchannels, and it cooperatively transmits packets with the secondary user and exploits the free band assigned by the control center to amplify-and-forward what it receives immediately. Under this scenario, the outage probability of the cooperative transmission pair of the primary and secondary transmitters is derived. The numerical simulation of the outage probabilities as a function of primary transmission probability ps, power allocation ratio ξ between the primary and secondary users, and the numbers of the primary and secondary users are given respectively. The results show that the optimal system performance is achieved under the conditions of ξ=0.5 and the numbers of the primary and the secondary users being equal.