Research On Cooperative Two-way Relay And Energy-efficiency Resource Allocation In Cognitive Radio Network

Wireless communication technology has developed rapidly in the past century.Wireless communication network and application have become an important part of people's daily life.With the growth of wireless communication service demand,the future wireless communication network will not only face the challenge of wireless spectrum resource shortage,but also face the problem of how to reduce the energy consumption.Cognitive radio(CR)technology can improve the spectrum utilization.Combining it with wireless power transmission technology is a hot research direction of green communication.Aiming at the problems of energy consumption and interference in cognitive radio networks,relay cooperation and resource allocation are studied in this paper.The main work is as follows:1.Aiming at the problem of energy consumption and transmission performance in CRNs,a bidirectional relay cooperative scheme in underlay CRN is studied,in which two secondary users(SUs)exchange information through bidirectional relay nodes with energy harvesting.Firstly,single-relay selection(SRS)and multi-relay selection(MRS)schemes are proposed to select the proper relays.The relay or relay set collect energy from the received signal and utilize it to forward information,which can significantly reduce the transmission power of the secondary network(SN).Secondly,the closed upper bound expressions of outage probability of the SN in Rayleigh fading channel are derived by using the cumulative distribution function of the end-to-end SNR.Finally,Simulation results verify the analysis of outage performance,and there is an optimal energy harvesting period to minimize the outage probability of the SN.The proposed scheme has higher throughput for the SN and can improve energy efficiency(EE)of SUs.2.Furthermore,considering the co-channel interference and energy consumption caused by multiple SU pairs(D2D)reusing the spectrum resources of primary users(PUs)in underlay CRNs,a power allocation algorithm based on game theory for high energyefficient(EE)is proposed.Firstly,D2 D users reuse the uplink spectrum of PUs.Considering the transmission power competition between D2 D users and PUs in order to improve their own EE,the transmission power allocation problem is described as a noncooperative game.Secondly,the interference temperature threshold is regarded as the constraint of each user's power strategy,and the energy utility function is constructed,focusing on the optimization of EE.The Lagrange multiplier method and KKT condition are used to solve the optimal transmission power strategy set iteratively,so that the EE of each user can reach equilibrium.Finally,the influence of different parameters on energy efficiency is analyzed by simulation,and the advantages of the proposed algorithm in energy efficiency and system capacity are verified.