Research On Mode Selection And Resource Allocation Strategy In D2D Communication

With the rapid development of modern wireless communication technology,the problem of spectrum resource shortage is becoming more and more serious,especially with the widespread application of 5g.How to improve the utilization efficiency of existing spectrum resources has become the focus of current research.Therefore,D2D(device to device)as a direct technology of terminal devices has been paid more and more attention by communication researchers.D2D technology can greatly improve the utilization of system resources,relieve the pressure of base station(BS),and make the system have faster transmission rate and greater capacity.But the introduction of D2D into cellular system will bring a lot of interference to the original cellular users.Therefore,how to choose the appropriate communication mode and control the interference effectively for D2D becomes the key to improve the performance of the system.This paper focuses on the solution of the two key problems,mode selection and power control.The system capacity is considered as the index of this paper,and the power control and the method of selecting communication mode are developed.At first,considering the scenario of a cell,in order to control the transmit power of the cell users and the D2D pair,the D2D pair uses the uplink resources of the cell to complete the communication.The interference in the system is analyzed to meet the transmission power and signal to interference plus noise ratio,In the case of SINR constraint,this paper establishes a constrained optimization problem with the purpose of solving the maximum throughput and the transmission power as the variable,in which the joint restriction of power and SINR is to better reduce the interference.Then,an adaptive genetic algorithm is proposed,which adopts the real coding method,according to the nonlinear dynamic inertia weight strategy and the particle swarm optimization algorithm based on genetic algorithm The learning factor of anti cosine strategy changes the calculation methods of crossover operator and mutation operator respectively.At the same time,the excellent individual preservation scheme is added,which can effectively preserve the excellent genes appearing in the evolution process.According to the proposed algorithm to solve the optimization problem,the optimal transmit power is obtained.Simulation results show that the proposed algorithm can effectively improve the system throughput.This paper further studies the D2D power control of joint mode selection.Firstly,it analyzes whether the interference caused by D2D to BS exceeds the limit.In this paper,the appropriate communication mode is selected for each D2D pair by using SINR mode selection method,and the optimization problem aiming at system throughput is established.Secondly,an improved grey wolf optimizer(GWO)algorithm is proposed to solve the optimization problem,and the optimal transmit power of D2D and cellular users after mode selection is obtained.Firstly,the convergence factor in GWO is improved to make it nonlinear decreasing state.Secondly,the population update strategy is improved,and the improved scheme makes the algorithm have better global search ability.Simulation results show the effectiveness of the proposed algorithm.