Research On Power And Spectrum Allocation Performance In Cognitive Cooperative Relay Wireless Networks

In cognitive radio,cognitive users sense the surrounding wireless environment by using spectrum sensing,and then the cognitive users use dynamic spectrum access to access the authorized spectrum.Cognitive radio allows the cognitive users to access the authorized spectrum dynamically without affecting the communication of the primary users.This technology improves the utilization of the authorized frequency band,and alleviates the current shortage of spectrum effectively.Cooperative relay transmission has been identified as a promising solution for combating the shadowing effect.The combination of cognitive radio and cooperative relay transmission can further improve the system performance.However,the introduction of cognitive relay brings new problems,the most important of which is the allocation of power and spectrum.In addition,the location of the cooperative relay also has an important effect on the channel state between the communication nodes and has an effect on the allocation of power and spectrum too.To solve the above problems,the main contents of this paper are as follows:1)The optimal allocation of power and spectrum is studied in suggested cognitive cooperative relay wireless networks.In order to enable the cognitive user to access the authorized spectrum,the cognitive cooperative relay assists the authorized user transmit the data.To minimize the cognitive user system BER as the target,constraints of authorized system BER as a constant in order to ensure the communication quality.Carried out the optimal allocation of cognitive transmission power and authorized spectrum.2)In order to study the effect of cooperative relay location on system performance in cognitive cooperative relay wireless networks,a scheme of allocation of power and spectrum based on cooperative relay location is proposed.The location of the cooperative relay directly affects the channel state between the communication nodes,which also affects the allocation of power and spectrum.In this paper,the channel gain model is constructed and the position of the optimal cooperative relay is determined by traversal search method.Then,the power and spectrum are reasonably allocated on the basis of the optimal relay position.The proposed scheme takes full advantage of the power and spectrum,thus further improves the performance of the system.