双向协作中继网络的中继选择和功率分配策略的研究

发布时间：2018-07-11 15:33

本文选题：协作网络 + 双向中继　；参考：《江苏大学》2017年硕士论文

【摘要】：如今移动用户不断增多,业务需求质量也不断提高,而现实中无线频谱资源紧缺和无线传输环境恶化的问题却日趋严峻。协作通信的出现提供了利用空间资源的新方法,它通过协作的方式使多个参与通信的实体间来共享有限资源从而提高无线资源利用率。双向中继相比于单向中继,可以实现信号的双向传输与交换,且有更高的频谱利用率,因此近几年涌现了大量针对双向协作中继网络的研究。由于系统资源有限,合理的功率分配可以改善网络性能。选择适合的中继节点也有利于合理的利用系统资源,降低传输链路间干扰。论文主要针对双向协作中继网络的中继选择和功率分配策略的优化进行研究。主要的研究工作包括:由于传统双向协作中继网络的信道容量、中断概率、信噪比(SNR,Signal To Noise Ratio)以及误符号率(SER,Symbol Error Ratio)等系统性能不够理想。为了改善系统的性能,一方面本文针对中继选择策略的研究,提出了基于最小化中断概率的最优中继数目的多中继选择算法,该算法将候选中继的中断概率与系统设定的中断概率阀值进行比较,使中断概率最小,从而得到最优的中继数目。仿真结果显示,改进的算法相对提高了系统性能。另一方面针对功率分配策略的研究,相比于传统单一性能角度分析的基于最小化误符号率(SER)和最大化系统容量的功率分配策略,提出了综合误符号率(SER)和系统容量的联合功率分配策略,通过仿真结果得出本文所提策略相对改善了系统容量、中断概率、误符号率(SER)等系统性能。为了进一步提高双向协作中继网络的系统性能,通过采用融合编码和路由的网络编码可进一步节省传输能量、提升网络吞吐量等。而在实际多径衰落信道之中,难免有传输误差,而导致网络编码的容量增益降低。引入冗余的信道编码可进行纠错,从而提高链路传输的质量,其中Turbo码作为性能较好的编码方式,本文就把协作通信、网络编码以及Turbo码结合来综合研究,提出了基于联合Turbo-网络编码的双向协作中继网络的改进策略。仿真结果表明:与传统网络编码方式相比,本文所提的基于联合Turbo-网络编码的策略相对提高了传输容量,改善了系统的传输性能。
[Abstract]:Nowadays, the number of mobile users is increasing and the service quality is improving. However, in reality, the shortage of wireless spectrum resources and the deterioration of wireless transmission environment are becoming more and more serious. The emergence of cooperative communication provides a new way to utilize space resources. It enables multiple entities participating in the communication to share limited resources by means of collaboration so as to improve the utilization of wireless resources. Compared with one-way relay, bidirectional relay can transmit and exchange signals in both directions and has higher spectral efficiency. Therefore, a large number of researches on bidirectional cooperative relay networks have emerged in recent years. Due to the limited system resources, reasonable power allocation can improve the network performance. The selection of suitable relay nodes is also beneficial to the rational utilization of system resources and the reduction of inter-link interference. This paper mainly focuses on the relay selection and power allocation strategy optimization in bidirectional cooperative relay networks. The main research work includes: the performance of traditional two-way cooperative relay network such as channel capacity, interrupt probability, SNR (SNR signal to noise ratio) and server symbol error ratio are not satisfactory. In order to improve the performance of the system, on the one hand, aiming at the research of relay selection strategy, this paper proposes an optimal number of relay selection algorithm based on minimizing interrupt probability. In this algorithm, the outage probability of the candidate relay is compared with the outage probability threshold set by the system, so that the outage probability is minimized and the optimal number of relays is obtained. The simulation results show that the improved algorithm improves the performance of the system. On the other hand, compared with the traditional single performance analysis based on minimizing symbol error rate (SER) and maximizing system capacity, the power allocation strategy is based on the power allocation strategy. A combined power allocation strategy combining symbol error rate (SER) and system capacity is proposed. The simulation results show that the proposed strategy can improve the system performance such as system capacity, interrupt probability and symbol error rate (SER). In order to further improve the system performance of bidirectional cooperative relay networks, network coding with fusion coding and routing can further save transmission energy and improve network throughput. In the real multipath fading channel, the transmission error is inevitable, which leads to the decrease of the capacity gain of the network coding. The redundant channel coding can be used to correct errors and improve the quality of link transmission. Turbo code is used as a better coding method. In this paper, the cooperative communication, network coding and Turbo code are combined to study comprehensively. An improved strategy for bidirectional cooperative relay networks based on joint Turbo-network coding is proposed. The simulation results show that the proposed strategy based on joint Turbo-network coding can improve the transmission capacity and performance of the system, compared with the traditional network coding method.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.5

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