分析Rayleigh信道下分集/无分集的AF(Amplify and Forward)和DF(Decode and Forward)模式单中继传输的平均中断概率,给出解析表达式。在总功率约束下推导了4种模式下的统计最优功率分配的解析表达式来最小化系统的平均中断概率,并提出...分析Rayleigh信道下分集/无分集的AF(Amplify and Forward)和DF(Decode and Forward)模式单中继传输的平均中断概率,给出解析表达式。在总功率约束下推导了4种模式下的统计最优功率分配的解析表达式来最小化系统的平均中断概率,并提出通过最佳中继选择进一步降低系统的平均中断概率。仿真结果表明,虽然AF模式和分集DF模式下的功率分配是在高发送SNR条件下推导的,但其在低发送SNR下依然有效;相对于固定功率分配,依据节点统计信息的最优功率分配可以有效降低系统的平均中断概率,多中继网络中的最佳节点选择进一步降低了系统的平均中断概率。展开更多
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...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.展开更多
文摘分析Rayleigh信道下分集/无分集的AF(Amplify and Forward)和DF(Decode and Forward)模式单中继传输的平均中断概率,给出解析表达式。在总功率约束下推导了4种模式下的统计最优功率分配的解析表达式来最小化系统的平均中断概率,并提出通过最佳中继选择进一步降低系统的平均中断概率。仿真结果表明,虽然AF模式和分集DF模式下的功率分配是在高发送SNR条件下推导的,但其在低发送SNR下依然有效;相对于固定功率分配,依据节点统计信息的最优功率分配可以有效降低系统的平均中断概率,多中继网络中的最佳节点选择进一步降低了系统的平均中断概率。
基金The National Natural Science Foundation of China (No.60972026)the Natural Science Foundation of Jiangsu Province (No.BK2008289)Specialized Research Fund for the Doctoral Program ofHigher Education (No.20090092110009)
文摘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.
