The Research On Power Control And Channel Capacity Of Cognitive Radio

With the perpetual development of the contemporary communication technology and the high frequency of the information interaction,the resource of spectrum has become extreme lack.Cognitive radio(CR)is a revolutionary technology that promises to alleviate the radio spectrum shortage problem by improving the spectrum utilization.The main duty of CR is sensing the radio spectrum resource and utilizing the idle spectrum to communicate.The dissertation has five sections,the main work is mentioned followed:In section one,the dissertation summarizes the fundamental theory and the background materials on CR,then discuss the system model.With regard the key technologies of CR respectively the most important is sensing spectrum technology that is the fundamental of CR.In section two,brief instruction of spectrum sensing technology is given.Several typical detection methods are analyzed and compared primarily from the aspect of principle,Then dissertation bring in sensing based on interference temperature,cooperative detection and signal coverage sensing.In section three,by introducing the class of available spectrum("white" and "gray") spatial multiuse of the same spectrum is also considered,and develop an approach to control the transmit power of cognitive radio by using the side information of spectrum sensing. Power control can effectively avoid the interference to achieve the reuse of spectrum.The main propose of researching the cognitive radio is to allow cognitive user utilizing the licensed spectrum to communication and acquiring channel capacity.So this dissertation has a final simulation and analyzing of the channel capacity in various channel fading conditions.Then a new system modern is offered,and simulation of channel capacity is made by MATLAB,the upper limit of channel capacity under average power control is given.The power allocation arithmetic is used to maximize the channel capacity in channel fading environment.