认知无线电网络中感知时间与功率分配的优化

针对多协作用户多信道的情况，讨论了当信道增益固定时，各子信道之间检测时间、总检测时间与传输时间，以及各子信道之间功率分配的问题。区别于以往的单独优化算法，提出了各参数的联合优化算法。以信道容量为目标函数，给出了最优的时间和功率分配算法。实验结果表明，提出的算法能够实现频谱接入并且极大地提高了次用户系统的总信道容量。表明功率分配与信道上主用户占用的概率有关，而时间分配则与信道上主用户接收信噪比以及传输时自身的信噪比有关。在多认知用户网络中，参与合作的用户越多，接收与传输信噪比越高，次用户系统的总信道容量越大。对于认知无线电网络，还考虑了整体的实现。

Optimization of power and time allocation in cognitive radio networks

In the scenario of multiple secondary users and channels,under fixed channel gains,sensing time between the multiple channels,total sensing time versus the transmission time,and the power allocation are analyzed for the cognitive radio networks.Different from the separate optimization in the previous papers,joint parameters optimization is proposed in this paper.The achievable rate of the secondary network is maximized to obtain the optimal time and power allocation parameters.Numerical investigation shows that the proposed scheme can achieve spectrum sensing and the optimization process significantly improves the rate of the secondary network.The power allocation is related to the prior probability of presence of primary user,and the time allocation is related to the Signal to Noise Ratio(SNR)of the received signal and the channel gain of the transmission channel.In the multiple user secondary networks,it can be concluded that,more number of secondary users and higher SNR can result in larger rate of the secondary system.The realization of the proposed scheme is also considered.