协作频谱感知在认知网络中的应用

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。在认知无线电网络中，认知用户（次用户）必须连续地监控频谱，检测主用户是否存在。如果主用户存在，次用户必须尽快地退出该频段，从而不影响主用户。在文中采用一种协作机制，即两用户进行协作频谱感知，从而提高主用户的检测率，减少了检测时间，并且得到捷变增益。我们用Matlab给出仿真结果。

Cooperative Spectrum Sensing in Cognitive Radio Network

Cognitive radio（CR） can sense the environment. CR uses spectrum sensing to find the spectrum hole so that it can adapt to the environment. In cognitive radio network, cognitive users（secondary users） must continuously monitor the spectrum to find the presence of the primary user. If primary user is present, the cognitive users must vacant the spectrum band so that it does not produce influence on the primary user. In this paper, a cooperative scheme, that is, the two-user cooperative spectrum sensing is used, which could reduce the detection time, enhance the detection probability and obtain the agility gain. The simulation results are acquired by using Matlab.