Research On The Key Issus In Emergency System Based On Cognitive Radio

The development of emergency communication system has become very urgent,due to frequent disasters and emergencies happened among world and China recentyears. It meets the bottleneck,the tension of radio spectrum resources. The cognitiveradio technology is going to help emergency communication to solve the problem. Thispaper will present an in-depth study and solution according to characteristics of theemergency communications system from aspects among system establishment,information transmission control and spectrum sensing.By analyzing the demand for Cognitive Radio of emergency communicationstechnology, this paper designs a set of solutions based on cognitive radio technology. Inthis scenario, emergency communication system has several subsystems according todifferent regions and functions. For each subsystem,functions, physical layer and datalink layer are designed. And a dynamic channel design also will be discussed to solvethe problem of control channel congestion caused by large number of users in short time.The way to realize it is that control information is transferred to the data transmissionsystem dynamically,to improve the control channel capacity.The unreliability issue caused by complex electromagnetic and large amount ofusers is addressed by weighted clustering-based cooperative spectrum sensing method.The cluster head will be selected based on the principle of clustering. And the result’sdetection will be sent to the cluster according to the findings of a two-threshold method.The node result will be tested and integrated by OR or AND rules and sent to thegateway,i.e.the control center of subsystem. In order to reduce the impact of unreliablenodes,the gateway is going to take K out of N convergency criterial with reputationweighted, therefore improve the detection accuracy.Finally, MATLAB simulation isdone to verify the excellent properties of the algorithm.