Research On Buffer-aided Relay Link Selection Strategy Based On CSI

Buffer-aided relay,which temporarily stores the transmission data from the source node through the configuration buffer at the relay,so that the relay can adaptively select to receive or send data so that the system can fully utilize the data status of each link channel state information for flexible data transmission and obtain higher performance gain.There are many non-ideal transmission scenarios in the actual communication system,such as channel estimation errors,eavesdroppers in the network,simultaneous information transmission and reception to generate interference,and the influence of the secondary node's communication process on the major nodes in the cognitive network.This paper mainly studies the buffer-aided relay adaptive rate transmission strategy and the relay selection strategy of the multi-relay system under non-ideal scenarios and different communication performance requirements.Firstly,this paper gives a brief overview of the three-node model and multi-node model of the buffer-aided relay.For the single-relay model,the transmission process is briefly introduced.For the multi-relay system,several common relay selection strategies are introduced.Compares the transmission performance of different strategies.The simulation verifies the performance advantages of buffer-aided relays due to the rational allocation of data sending nodes.Compared with different strategies,the max-link selection process is simple and the performance exceeds the traditional selection strategy,but the data transmission delay increases;The strategy of link selection based on the buffer storage information through a relatively complex screening process,compared with the traditional program can improve the delay and outage probability performance.Then,for the three-node buffer-aided auxiliary relay communication model,in the case of half-duplex relay transmission,adaptive transmission strategies and fixed-rate transmission strategies are analyzed.The throughput performance and outage probability performance of the system is better than the traditional relay.The buffer-aided relay adaptive transmission strategy has more obvious advantages in the case of link performance asymmetry.For the situation where channel state information is estimated to be erroneous,this paper analyzes its impact on system performance under the fixed-rate transmission and improves the parameter selection process.In order to optimize the system's transmission rate and outage probability;for the presence of eavesdropping nodes,this paper proposes an adaptive transmission strategy with the goal of confidentiality and rate and establishes the optimization problem through the buffer data queue stability conditions to obtain the best transmission strategy.For a full-duplex buffer-aided relay system,this paper aims at optimizing the throughput and considers the impact of direct links on the system.A full-duplex buffer-aided relay transmission scheme with adaptive power allocation is proposed and the simulation results are proved.Finally,for the multi-node buffer-aided relay communication model,under the premise of the half-duplex operation mode,the performance of the max-link transmission strategy is analyzed,including outage probability,throughput,and delay,and there are delay limitation and link asymmetry.While the control node can only obtain part of the channel state information,the improvement strategy of the max-link transmission strategy is given.According to the Markov analysis architecture of the multi-relay system,the expressions of system outage probability,throughput,and delay under different conditions are deduced.A relay selection strategy under asymmetric link conditions is proposed;the simulation results show that the proposed strategy can achieve lower outage probability under asymmetric conditions.