Performance Analysis And Protocol Selection Of SWIPT Cooperative System Under Finite Sensitivity EH Model

Cooperative communication technology is a technology that uses relays for cooperative transmission,which can expand communication coverage and allow terminals to gain diversity gain,thereby improving system capacity,reliability,and energy efficiency performance.However,the limited battery life of relay nodes has greatly limited the development of this technology.The emergence of wireless energy communication(Simultaneous Wireless Information and Power Transfer,SWIPT)technology has effectively alleviated this problem.Utilizing the characteristics of radio frequency(RF)signals with both energy and carrying information,SWIPT technology enables relay nodes to collect energy while receiving information,thereby supplementing the node's battery energy and effectively extending the life of the wireless communication network..At this stage,research on SWIPT technology has achieved certain results,but the linear energy harvesting(EH)model or the nonlinear energy harvesting model used in most studies currently ignores the important feature of the limited sensitivity of EH circuits.In the low input power state,the magnitude of sensitivity has a significant effect on the performance of the entire communication system.Therefore,considering the limited energy receiving sensitivity,this paper studies the transmission performance of the single relay SWIPT cooperative communication system under the nonlinear EH model,and analyzes the impact of resource allocation parameters on the system interruption performance.Communication is extended to multi-relay communication,and the optimization of multi-relay resource allocation is studied.The main work of this article is as follows:1.For the single-relay SWIPT cooperative communication system,considering the limited energy receiving sensitivity,the interruption performance under the nonlinear EH model is studied.There are two kinds of relay protocols for traditional cooperative communication,which are Amplify-and-Forward(AF)and Decode-and-Forward(DF).Based on the Rayleigh channel model,this paper derives the outage probability expression of the relay node using the DF relay protocol to forward the information to the destination node.At the same time,it compares with the system outage probability under the linear EH model,and the analytical expression based on the outage probability The effects of various resource configuration parameters on system performance are studied.Monte Carlo simulation experiments show the correctness of the derivation expressions in this paper.The simulation results show that:(1)the location of the relay node,the power splitting factor,the transmission power of the source node and other parameters have a significant impact on the interrupt performance of the system;)The interruption system of the limited sensitivity nonlinear EH model system will be worse than the infinite sensitivity linear EH model system,but it is closer to the actual situation and has more reference value;(3)The interruption probability of the system is about the power division factor,medium Following the concave function of the node deployment position,there is an optimal solution that minimizes the system outage probability.2.For the multi-relay two-hop SWIPT communication system,this paper presents a joint optimization algorithm of hybrid relay protocol and dynamic power splitting factor,and further verifies the feasibility of the algorithm by modeling and solving the objective function.In the case where the signal-to-noise ratio of the link from the source node to the relay node cannot be determined,we propose to use the critical power splitting factor that the relay node can successfully decode to determine the relay forwarding protocol of the relay node.After that,the range of the power splitting factor is further limited to ensure that the input power of the energy receiver is between the sensitivity and the saturation input threshold,so that the energy receiver can work normally and does not waste resources due to saturation.On this basis In the above,we optimized the power splitting factor to maximize the transmission rate of the destination node.The simulation results show that the destination node can achieve a higher transmission rate than the multi-relay system using a single relay forwarding protocol and a dynamic power splitting factor compared to a single relay forwarding protocol with a fixed power splitting factor.It should be pointed out that the research work in this paper is based on the nonlinear EH model with limited sensitivity,the energy harvesting model is more in line with the actual situation,and the solution is more difficult.