【作者】 陈兴林；

【导师】 王钢；

【作者基本信息】 哈尔滨工业大学 ， 信息与通信工程， 2018， 硕士

【摘要】 缓冲中继,通过中继处配置缓冲器临时存储来自源节点的发送数据,使得中继可以自适应选择接收或发送数据,使得系统能够充分利用各链路信道状态(Channel State Information,CSI)信息灵活进行数据传输,获得更高的性能增益。实际通信系统中往往存在多种非理想传输场景。如信道估计出现误差、网络中存在窃听者、信息同时收发产生干扰、认知网络中次要节点通信过程对主要节点的影响等等。本文主要研究在非理想场景及不同通信性能需求下的缓冲中继自适应速率传输策略和多中继系统的中继选择策略。首先,本文对缓冲辅助中继的三节点模型和多节点模型进行了简要概述,针对单中继模型,简单介绍了传输过程;对于多中继系统介绍了几种常见的中继选择策略,并对比了不同策略的传输性能。仿真验证了缓冲中继由于合理分配数据发送节点带来的性能优势,对比不同策略,最大链路(max-link)选择过程简单,性能超过传统选择策略,但是数据传输延迟增加;基于缓冲器存储信息进行链路选择的策略通过相对复杂的筛选过程,对比传统方案在延迟和中断概率性能上都获得了提升。其次,针对三节点缓冲辅助中继通信模型,在半双工中继传输情况下,分析了自适应传输策略和固定速率传输策略,系统的吞吐量性能和中断概率性能均优于传统中继,缓冲中继的自适应传输策略在链路性能不对称的情况下优势更加明显;针对信道状态信息估计出错的情况,本文分析了其对固定速率传输情况下系统性能的影响,并改进参数选择过程以优化系统的传输速率和中断概率;针对有窃听节点存在的情况,本文提出了以保密和速率为目标的自适应链路选择传输策略,通过缓冲器数据队列稳定条件建立最优化问题模型最终得到最佳传输策略。对于全双工缓冲中继系统,本文考虑直达链路的影响,提出了一种自适应功率分配的全双工缓冲中继传输策略,并仿真验证了其性能优势。最后,针对多节点缓冲中继通信模型,在半双工工作模式的前提下,分析了max-link传输策略的性能,包括中断概率,吞吐量和延迟,并在有延迟限制、链路不对称和控制节点只能获取部分信道状态信息的情况下,给出了max-link改进策略,根据多中继系统的马尔可夫分析架构,推导了不同条件下系统中断概率,吞吐量和延迟的表达式。提出了非对称链路条件下的中继选择策略;仿真结果表明,在非对称条件下,改进策略能取得更低中断概率。更多还原

【Abstract】 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.更多还原