With the rapid development of wireless communication technology,there is increasing demand for spectrum. The spectrum has become increasingly tense and even exhausted because it is a limited natural resource. To solve this contradiction,the current spectrum management method must be improved. Cognitive Radio ( CR) is one of the most promising techniques to solve the spectrum scarcity. Existing researches have focused on improving the spectrum efficiency of cognitive radio system. With the continuous improvement of the spectrum efficiency,the system energy consumption also presents exponential growth. For energy-constrained nodes,it is necessary to im-prove the energy efficiency. Therefore,the energy efficiency model of cognitive radio system is set up under the cooperative spectrum sensing scenario which exits misdetection and false alarm. Furthermore,the procedure of cooperative spectrum sensing,spectrum handoff and transmission is considered jointly. By optimizing the sensing time,the maximum energy efficiency of the system is achieved. The sim-ulation results prove the existence of an optimal sensing time,which enables the system to achieve the maximum energy efficiency.%随着无线通信技术的飞速发展,人们对于频谱的需求不断增加.而频谱资源是一种有限的自然资源,其日趋紧张甚至枯竭已成为不争的事实,而真正要解决这种矛盾,必须对现在的频谱管理方法进行改进.认知无线电技术是解决频谱短缺的最有前景的技术之一.现有研究多着眼于提高认知无线电系统的频谱效率,但随着频谱效率的不断提高,系统能耗也呈现指数级增长,对于能量受限节点来说必须要提高系统能效.为此,针对协作频谱感知场景同时考虑认知用户非理想感知的情况,建立了认知无线电系统的能量效率模型;在此基础上,综合考虑频谱感知、频谱切换和数据传输过程,通过优化频谱感知时间,使得系统能效达到最大.仿真结果表明,存在最优的感知时间,使得系统能效达到最大.
展开▼
