Research On Key Technologies Of Relay Cooperative Communication With Channel Estimation Error

With the explosive growth of the number of mobile terminals,the social demand for mobile networks is increasing,which makes the existing mobile network system more burdensome.However,in practical engineering applications,at the same time,only a small number of devices may be in communication state,while most of the terminal devices are in idle state.How to effectively use idle devices to participate in signal transmission and improve bandwidth utilization has become a research hotspot in recent years.To this end,cooperative communication technology has emerged.It is noteworthy that the current research on cooperative communication mainly focuses on the ideal situation,so it is not applicable to practical engineering applications.In this context,in order to be more practical,this paper mainly studies the key technologies of cooperative relay communication based on channel estimation error and hardware imperfection to improve system performance.The main research work and innovations are as follows:Firstly,the reliability of multi-relay cooperative communication system based on channel estimation error is studied,and an optimal multi-relay selection scheme is proposed in this scenario.At the same time,the performance of the optimal relay selection scheme in the same scenario is compared with that of the traditional maximum ratio combination selection scheme.The asymptotic solution of outage probability in the system based on the optimal multi-relay selection scheme is deduced theoretically.Finally,the simulation results show that the channel estimation error has a great influence on the system performance under the same SNR.At the same time,the simulation results also show that the optimal multi-relay selection scheme significantly improves the reliability of the cooperative communication system compared with the traditional maximum ratio combination scheme under the same channel estimation error conditions.Secondly,the physical layer security of relay network based on channel estimation error is discussed.On this basis,an optimal single relay selection scheme is proposed.The system security outage probability of the optimal single relay selection scheme is deduced theoretically,and the performance of the optimal single relay selection scheme and the traditional round robin scheduling scheme is compared.The simulation results show that when the channel estimation error and SNR are fixed,the performance of the optimal single relay selection scheme is obviously better than that of the traditional round robin scheduling scheme.At the same time,in the presence of eavesdropping nodes,the scheme proposed in this chapter can improve the security performance of the system to a certain extent.Finally,the performance of relay network based on channel estimation error in hardware imperfect environment is explored.In this scenario,the best single relay selection scheme and the best multi-relay selection scheme are proposed respectively.The closed-form solutions of outage probability of the two schemes are deduced,and the performance of the two schemes,as well as the influence of hardware impairment and channel estimation error on the performance of the system are compared.Finally,simulation results show that under the same conditions,the performance of the optimal multi-relay selection scheme is better than that of the optimal single-relay selection scheme.At the same time,under certain SNR and channel estimation errors,the performance of cooperative communication system will deteriorate with the increase of hardware impairment.