Research On Relay Selection And Resource Allocation Algorithm In Two-way Relaying Networks

With the increasing number of wireless services,spectrum resources become scarce.Cognitive radio technology can be used to detect idle spectrum to alleviate the scarcity of spectrum.Cooperative relay communication technology uses relay to cooperate the information transmission of the source node to improve the communication capacity.It can be used to resist multipath fading,improve system performance,increase cell coverage area.At the same time,relay has the characteristics of low cost and flexible deployment.Two-way communication technology can exchange signals of two users and improve spectrum utilization.Energy harvesting technology is an effective way to prolong the life of the network.The introduction of these four technologies can promote the realization of green communication.In this paper,relay selection and resource allocation in two-way wireless networks are studied.The main work is as follows:1.Relay selection and power allocation algorithm for energy harvesting two-way relaying networks is proposed.Relay uses time switching protocol to haverst energy radiated from source and destination which can be used for two-way cooperative communication.In two-way relaying networks,under the constraints of finite-size data buffer and finite-size battery,the optimization model of the maximum system throughput is established to solve the relay selection and power allocation.The proposed algorithm uses the Lagrange multiplier method to solve the optimal power allocation,and uses the maximum marginal effect of the system to solve the optimal relay selection.The simulation results show that reasonable transmission time,buffer and battery capacity can effectively improve system sum-throughput.2.Relay selection and spectrum allocation algorithm for overlay two-way relaying networks is proposed.In overlay cognitive radio networks,secondary user can only use the spectrum to transmit information only when the two-way communication between primary user is completed.First,considering the QoS constraint of primary user,the optimal model of secondary user throughput is established to allocate spectrum resource,and secondary user with the largest throughput is selected as the relay of primary user.Then when primary user or secondary user does not satisfy the QoS constraints,link outage occurs.The performance of the proposed algorithm is analyzed by calculating the outageprobability of the primary user and secondary user.The simulation results show that the outage probability of primary user and secondary user is related to the number of relays,QoS and so on.