认知无线电中能效优先的多用户随机接入方法  

Energy efficient multi-user random access in cognitive radio

作　　者：甘小莺[1] 陈时阳[1] 王路洋[1] 金荣洪[1] 

机构地区：[1]上海交通大学电子工程系,上海200240

出　　处：《电波科学学报》2013年第4期648-655,共8页Chinese Journal of Radio Science

基　　金：国家自然科学基金(61102052;60972050);国家基础研究973项目(2010CB731803);新一代宽带无线移动通信网重大专项(2010ZX03002-007-01)资助

摘　　要：为了提高认知无线电网络中用户随机接入的能量效率,提出了一种能效优先的多用户随机接入方法.该方法基于信道的时变特性,在构建多用户随机接入能耗模型的基础上,利用最优停止理论,可实现接入算法能量效率的最大化.通过研究发现,该方法是一个基于门限的接入判决准则.在此基础上,研究了最大化能量效率和最大化吞吐量之间的关系,推导了使能量效率和吞吐量同时达到最大的充分条件.数值计算结果表明:如果传输功率远大于信道竞争功率和探测功率,则当系统实现吞吐量最大化时,能量效率损失较小.并研究了以用户为中心模式下,用户行为自私性对系统级能量效率的影响.数值结果显示,当用户数增大时,由用户行为自私性带来的相对损失百分比小于10%.When investigating cognitive radio networks, in order to improve the en-ergy efficiency of cognitive users with random access, we propose an energy effi-cient multi-user random access method which is based on the time-varying charac-teristic of channels. An energy consumption model for multi user random access is set up. We use optimal stopping theory to analyze the maximum energy efficiency. It shows that the optimal scheduling scheme is a pure threshold policy, which can be obtained by adopting an iterative algorithm. We also investigate the tradeoff be- tween energy efficiency maximization and throughput maximization. A sufficient condition is offered where energy efficiency and throughput can be maximized sim- ultaneously. According to numerical results, it is found that when the transmission power is relatively large compared with contention power and probing power, we are able to maximize the throughput without an obvious degradation on energy effi-ciency. Furthermore, when users＇ selfish behaviors are considered, we formulate a user-centric model, in which the loss of energy efficiency is less than 10% compared with network-centric case when the number of users grows.

关 键 词：认知无线电 能量效率 随机接入 多用户 

分 类 号：TN92[电子电信—通信与信息系统]