The Study Of Cooperation Spectrum Leasing Technology In Cognitive Wireless Network

In recent years,due to the diversified application of radio business in many areas and the rising number of communication users,the existing limited spectrum resources become more and more unable to meet the requirements of the modern communication system.In addition,duo to the static spectrum allocation model makes the authorized users occupy authorization service exclusively,the spectrum in the network is not evenly allocated,resulting in a waste of the spectrum resources.According to the above phenomenon,some scholars proposed to use cognitive radio technology to improve the utilization rate of network bandwidth resources through dynamic spectrum sharing between users.In order to realize the dynamic spectrum sharing,the spectrum leasing technology allows the Primary User(PU)to allocate part of the spectrum to the Secondary User(SU),while requiring Secondary User as a relay to help Primary User to communicate.Firstly,this paper studies the simple spectrum leasing model which is composed of single PU and single SU.This model requires the PU to choose the best cognition user in cognitive network as the cognitive relay.In order to avoid the cooperative cheating behavior of cognitive user,this paper proposes the collaborative spectrum leasing algorithm based on the credibility.This algorithm updates the reputation value of cognitive users according to their cooperative behavior at the end of each round of game,and the primary user selects the optimal cognitive collaboration relay according to the reputation value of cognitive users and the channel quality.In the process of cooperative forwarding,in order to achieve maximum transmission rate,the primary user allocates part of time slot to cognitive relay,and cognitive relay allocated power on the basis of maintaining its good reputation value and maximizing its own transmission rate.Finally,this paper solves the benefit optimization problems between PU and SU by using the principle of Stackelberg game,and finds the equilibrium solution to realize the “win-win” of the primary user and the secondary user.Then,further research is made on the spectrum leasing model which is involved in the cooperation of multiple cognitive users.In order to ensure the communication quality of primary users,secondary users carry out collaborate retransmission when the primary user's communication failed.A new spectrum leasing model which is based on the retransmission and including resource exchange and currency exchange is proposed In view of the problem of retransmission delay and user's selfishness.In this model,the primary users will lease the retransmission time slot to cognitive users,cognitive users compete for the remaining time slot for their own communication after participating in collaborative retransmission.On the basis of the Stackelberg game model,cognitive users need to pay the price to authorized network for using spectrum resources,the primary users also need to compensate for cognitive users' collaboration retransmission.This paper verifies and discusses the existence and uniqueness of the Nash equilibrium solution,and finds the equilibrium solution and its corresponding constraints.Numerical simulation proves that the proposed model can greatly improve the transmission rate and economic benefits of primary user and cognitive users.