Research On Cooperative Spectrum Sensing Of Cognitive Radio

With the widely application of wireless technology in mobile communication, as a non-renewable resource, radio spectrum resource becomes more and more scarce. On the other hand, due to the current fixed spectrum allocation policy, the average utilization rate of spectrum resources is very low, and extremely uneven. Cognitive radio technology can improve the spectrum utilization and alleviate spectrum resource scarce. So it has been attracted more and more attention.Spectrum sensing is first step for realization of cognitive radio. Spectrum sensing technology of cognitive radio is discussed in this thesis. Firstly, single-user local spectrum sensing method is analyzed, including the transmitter spectral detection and receiver spectral detection. In order to solve the poor performance of single-user spectrum sensing caused by the shadow fading and improve the detection performance, the thesis then discusses several methods of cooperative spectrum sensing, which are based on different data fusion criteria. Then two types of improved cooperative spectrum sensing methods are studied in the thesis, one is double-threshold cooperative spectrum sensing, the other is weighted cooperative spectrum sensing, double-threshold cooperative spectrum sensing adopts a centralized cooperative spectrum sensing, and weighted cooperative spectrum sensing adopts a combination of distributed and centralized cooperative spectrum sensing. It is shown by MATLAB simulation that compared with tradition cooperative spectrum sensing, the performance of the double-threshold co-spectrum sensing increases 3%-5%, and the weighted cooperative spectrum sensing increases 20%-30%.