认知无线电网络中接入控制和功率波束形成的联合优化

发布时间：2018-01-23 00:15

本文关键词： 认知无线电网络接入控制发射功率波束形成增广Lagrange函数 Armijo梯度下降法　出处：《计算机应用》2017年07期 　论文类型：期刊论文

【摘要】：在认知无线电网络中,针对鲁棒性的多用户接入控制和发射功率波束形成的联合优化问题,提出了基于熵函数光滑近似的联合优化方案。首先,利用L_0-范数最小化将接入控制和发射功率波束两个优化问题转化为一个联合优化问题;然后,利用基于熵函数光滑近似的方法对L_0-范数的非凸性及不连续性问题加以优化;最后,由于光滑可微的目标函数为单峰函数,将问题变形为增广Lagrange函数,利用Armijo梯度下降法得到问题的最优解。数值结果分析表明:新算法在信干噪比(SINR)较低时虽然所提算法的接入量无明显提高,但是在SINR较高时所提算法能显著降低发射功率并提高次用户的接入量。模型中对不确定的信道状态信息(CSI)加以分析,可以使网络更好地适应外界的变化,提高网络的可靠性,所提算法可以有效地实现网络资源的优化配置,提高网络性能。
[Abstract]:In cognitive radio networks, a joint optimization scheme based on the smooth approximation of entropy function is proposed to solve the joint optimization problem of robust multi-user access control and transmit power beamforming. The two optimization problems of access control and transmit power beam are transformed into a joint optimization problem by using LS-norm minimization. Then, the nonconvexity and discontinuity problems of L0-norm are optimized by using the smooth approximation of entropy function. Finally, because the smooth differentiable objective function is a unimodal function, the problem is deformed into an augmented Lagrange function. The Armijo gradient descent method is used to obtain the optimal solution of the problem. The numerical results show that the new algorithm has no significant increase in the access capacity of the proposed algorithm when the signal-to-noise ratio is low. However, the proposed algorithm can significantly reduce the transmission power and increase the access capacity of the secondary users when the SINR is high. The uncertain channel state information is analyzed in the model. It can make the network adapt to the changes of the outside world and improve the reliability of the network. The proposed algorithm can effectively realize the optimal allocation of network resources and improve the network performance.
【作者单位】：重庆邮电大学重庆市移动通信重点实验室;
【基金】：国家自然科学基金资助项目(61102062,61271260) 重庆市科委自然科学基金资助项目(cstc2015jcyjA40050)~~
【分类号】：TN925
【正文快照】： 0引言认知无线电技术通过频谱资源共享可以有效地提高频谱利用率[1]。在underlay频谱共享认知无线电网络中,认知用户(次用户)在不对主用户产生有害干扰下与授权用户(主用户)占用相同的频谱完成自身通信[2]。而且,随着多天线技术的发展,多输入多输出(Multiple-Input-Multiple-O

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