Resource Allocation Algorithm For Cognitive Radio Systems

With the progress of social science and technology,wireless radio technology has been gradually applied to all aspects of society life.The emergence of some new services has led to a rapid increase in the demand for wireless spectrum resources,so the tension of spectrum resources is becoming more and more serious.Fixed spectrum allocation is used in the traditional radio communication,resulting in low utilization of limited spectrum resource,which can not meet the diversity spectrum needs.Therefore a new technology based on the dynamic spectrum detection and distribution of cognitive radio communication technology is born.Resource allocation as one of the core technologies in cognitive radio has become one of the hottest research direction nowadays.And the combination of cognitive wireless and relay transmission technology can effectively reduce the wireless network multipath transmission caused by the decline and improve the signal to noise ratio.Therefore,this paper aims to maximize the capacity of the system and carried out research on resource allocation based on two way relay cognitive radio.The main innovations are as follows:(1)A resource allocation algorithm for power allocation and relay selection is proposed based on the choice of bidirectional relay cognitive radio system.By using the equivalence of the channel gain of the relay link,the allocation problem of the cognitive user and the base station transmit power is switched to the allocation problem of the relay transmission power.The transmission power of the relay is obtained according some known restrictions.Finally,the maximum system capacity is obtained by the optimization function of the single condition,and the corresponding selected relay is obtained according to the maximum system capacity.(2)In order to maximum capacity for the bidirectional relay cognitive radio communication system,a new relay arrangement selection and power quantization allocation method is proposed under the transmission power constraints for both the cognitive user node and the relay node and under primary user interference.Different from the previous works,the proposed method uses the number of permutations and combination of all relays and provides the power and interference constraint conditions for the user,therefore the maximum capacity is achieved.