协作频谱感知在认知网络中的应用

Cooperative spectrum sensing in cognitive radio network

认知无线电能够灵敏感知周围环境的变化,通过频谱感知功能发现频谱空洞,使得认知无线电能够与周围通信环境相适应。认知无线电最关键的技术就是主用户的感知。由于认知用户独立感知主用户的能力受到多径效应和阴影衰落的制约,主用户的检测率得不到提高。采用了一种协作机制,即3用户协作频谱感知,3个次用户以固定的TDMA模式发送数据到同一个接收器,当主用户出现时,3个次用户用能量检测的方法协作感知主用户的存在。仿真结果表明,3用户协作感知提高了主用户的检测率,同时减少了检测时间。

Cognitive radio（ CR）is sensitive to the changes of environment, and by using the spectrum sensing to find the spectrum hole, it can adapt to the environment. The key technology of cognitive radio is to detect the primary users. The ability that cognitive users detect the primary users is restricted by multi - path effect and shadow fading so that the detection probability of primary users cannot be enhanced. Hence, a cooperative scheme, namely the three users＇ cooperative spectrum sensing was adopted. Three secondary users transmit data to a common receiver in the TDMA mode, and when the primary users appear, the three secondary users can detect the primary users by energy detection. Simulation result indicates that three users＇ cooperative spectrum sensing enhance the detection probability and reduce the detection time.