双向中继系统中继选择和功率分配算法的分析与设计

发布时间：2018-07-10 00:08

本文选题：双向中继网络 + 网络编码　；参考：《南京邮电大学》2014年博士论文

【摘要】：随着人们对无线通信需求的不断增长，下一代无线通信系统需要提供更高的传输速率和可靠性。协作通信技术利用无线网络中的多个节点相互协作，能有效克服无线信道衰落，提高传输性能。网络编码技术利用无线传播媒介的广播特性能够明显提升双向中继协作通信的频谱效率。因此网络编码双向中继系统成为近年来通信领域研究的热点。本论文对网络编码双向中继系统中的中继选择和功率分配方案进行了深入研究。主要包括： 1）多对多中继（Multi-Pair Multi-Relay: MPMR）解码转发双向中继系统（Decode-and-Forward Two-Way Relaying Networks: DF-TWRN）中继选择和功率分配算法的分析和设计。首先建立DF-TWRN系统的性能解析分析方法，获得了高信噪比条件下单个DF双向子信道误码率的近似表达式。然后基于上述分析，，提出了一种双向误码率最低的功率分配方案，并将该方案应用于多对多中继系统，通过理论分析获得了该场景下通过最优功率分配得到的最小误码率的闭合解析解。理论分析和仿真结果表明新方案能有效降低双向误码率，同时在多对多中继系统中能获得低的运算复杂度和更好的误码性能。 2）非对称数据速率需求（Asymmetric Traffic Requirement: ATR）的双向放大转发中继系统（Amplify-and-Forward Two-Way Relaying Network: AF-TWRN）中继选择和功率分配联合算法的分析和设计。重点考虑了双向速率门限不同时对双向链路信噪比的优化，通过假设检验得到总功率约束下新的最优功率分配方案，并提出对应的中继选择准则。然后通过理论分析获得联合算法的系统中断概率的闭合表达式（或上下边界）；并基于已有的两种近似边界提出了新的近似分析方法，获得了更紧的中断概率下界。仿真结果证明了理论分析的正确性，表明新方案在ATR AF-TWRN网络中能够获得比其它方案更低的中断概率。同时通过新的近似边界得到的中断概率上下边界比已有的边界更紧，能更好地表征系统的中断性能。 3）过时信道信息（Outdated CSI）双向AF中继系统的多中继选择方案的分析和设计。首先建立Outdated CSIAF-TWRN系统模型，提出一种基于标准化门限的广义选择合并方案。通过理论分析和合理的近似获得了多中继选择方案下中断概率、平均误码率以及各态历经容量的上下边界，并分析该方案获得的分集增益。然后基于上述性能分析和比较，提出了一种自适应多中继选择方案。理论分析和仿真结果表明在Outdated CSI双向通信中，多中继选择可以获得更高的分集增益，同时最佳中继个数的自适应选择能够有效减少低信噪比区间多中继选择算法各态历经容量的损失，提升系统的中断性能。
[Abstract]:With the increasing demand for wireless communication, the next generation wireless communication systems need to provide higher transmission rate and reliability. Cooperative communication technology can effectively overcome the fading of wireless channel and improve transmission performance by using the cooperation of multiple nodes in wireless network. Network coding technology can significantly improve the spectrum efficiency of bidirectional relay cooperative communication by utilizing the broadcast characteristics of wireless media. Therefore, network coding bidirectional relay system has become a hot topic in the field of communication in recent years. In this paper, relay selection and power allocation schemes in network coded bidirectional relay systems are studied. The main contents are as follows: 1) the analysis and design of relay selection and power allocation algorithm for Decode-and-forward Two-Way Relaying Networks (DF-TWRN) decoding and forwarding bidirectional relay system (MPMR) with Multi-Pair Multi-Relay (MPMR). Firstly, an analytical method for performance analysis of DF-TWRN systems is established, and an approximate expression of BER for a single DF bidirectional subchannel with high SNR is obtained. Based on the above analysis, a power allocation scheme with the lowest bidirectional bit error rate (BER) is proposed and applied to many-to-many relay systems. The closed analytic solution of the minimum bit error rate obtained by optimal power allocation in this scenario is obtained by theoretical analysis. Theoretical analysis and simulation results show that the new scheme can effectively reduce the bidirectional bit error rate (BER). At the same time, low computational complexity and better bit error performance can be achieved in many-to-many relay systems. 2) Asymmetric Traffic requirements: ATR Two-Way Relaying Network: AF-TWRN Relay selection and Power performance of the Amplify-Forward Two-Way Relaying Network (AF-TWRN) Analysis and design of joint rate assignment algorithm. This paper focuses on the optimization of the signal-to-noise ratio (SNR) of bidirectional links with different bidirectional rate thresholds. A new optimal power allocation scheme with total power constraints is obtained by hypothesis testing and a corresponding relay selection criterion is proposed. Then, the closed expression (or upper and lower boundary) of the system interrupt probability of the joint algorithm is obtained by theoretical analysis, and a new approximate analysis method is proposed based on the two existing approximate boundaries, and a more compact lower bound of the interruption probability is obtained. The simulation results show that the new scheme can obtain lower outage probability than other schemes in ATR AF-TWRN network. At the same time, the upper and lower boundaries of the outage probability obtained by the new approximate boundary are more compact than the existing boundaries. It can better characterize the interrupt performance of the system. 3) the analysis and design of multi-relay selection scheme for outdated channel information (Outdated CSI) bidirectional AF relay system. Firstly, the model of Outdated CSIAF-TWRN system is established, and a generalized selective merging scheme based on standardized threshold is proposed. Through theoretical analysis and reasonable approximation, the interruption probability, the average bit error rate and the upper and lower boundaries of ergodic capacity of each state under the multi-relay selection scheme are obtained, and the diversity gain obtained by the scheme is analyzed. Then, an adaptive multi-relay selection scheme is proposed based on the above performance analysis and comparison. Theoretical analysis and simulation results show that multi-relay selection can obtain higher diversity gain in Outdated CSI bidirectional communication. At the same time the adaptive selection of the optimal number of relays can effectively reduce the loss of ergodic capacity of the multi-relay selection algorithm in the low SNR range and improve the interrupt performance of the system.
【学位授予单位】：南京邮电大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN929.5

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