新型混合星地协作通信研究

发布时间：2018-03-17 16:39

本文选题：星地通信　切入点：信道建模　出处：《华侨大学》2017年硕士论文　论文类型：学位论文

【摘要】：星地通信由于其覆盖范围广、通信距离长等优势受到了广泛关注,但复杂的星地信道以及遮蔽效应极大地限制了星地通信的性能。为了能够适应多变的星地通信环境,提升星地通信传输可靠性等要求,星地协作通信技术飞速发展起来。本文研究了星地协作通信技术,主要工作和创新点如下:(1)总结和归纳星地通信的基础知识。分析了星地信号传播方式以及影响信号传播的常见因素,给出了四种常用的描述星地信道传播特性的概率密度函数。总结了LDPC码在通信中的应用,并给出了二元速率兼容LDPC码的构造及译码算法。讨论了基于LDPC码的三种星地协作通信系统的优缺点,通过仿真比较不同协作系统的性能差异以及LDPC码参数对系统性能的影响。(2)设计新型星地衰落信道模型。采用加权正弦和法设计信道仿真器,并给出本文信道模型参数的推导过程。本文所提模型可以描述含有多种衰落情况的星地通信信道,并且解决了传统模型难以分析信道统计特性的难题。仿真结果表明,本文设计的信道模型的二阶统计特性和实测数据非常近似。(3)提出一种适用于星地衰落信道的编码协作方案。解决了传统星地协作通信中信道状态变化导致系统性能变差的问题。在三节点星地协作通信系统中引入混合自动重传请求(7)HARQ(8)协议。针对HARQ-II机制,推导了副本重传和增量重传方式的接收端最大传输速率和系统中断概率。对比发现,副本重传方案性能更优。在星地协作通信中将副本重传HARQ方案与速率兼容LDPC码相结合,设计一种码率自适应变化的星地通信协议。在该协议中,卫星和中继可以根据信道变化确定重传码率,实现系统码率的非线性增长,推导并比较了该协议下星地通信系统的中断概率和吞吐量理论性能。仿真验证本文协议与传统重传机制以及直传方式的误码率性能,结果表明,无论在何种星地衰落信道下,本文协议均可降低系统误码率与中断概率。
[Abstract]:Satellite communication due to its wide coverage, long communication distance and other advantages has attracted extensive attention, but the complexity of the satellite channel and the shadowing effect greatly limits the performance of satellite communication. In order to adapt to the changing environment of satellite communication, satellite communication to enhance transmission reliability requirements, satellite communication technology rapid development cooperation up. This paper studies the satellite cooperative technology, the main work and innovation are as follows: (1) summing up the basic knowledge of satellite ground communications. It analyses the common factors of satellite signal propagation and signal propagation effects, gives the probability density function of four kinds of commonly used to describe satellite channel propagation characteristics. Summarizes the application of LDPC codes in communication, and gives two yuan rate compatible structure and decoding algorithm of LDPC codes. Discuss the advantages and disadvantages of the three satellite cooperative communication system based on LDPC code, by simulation comparison Effect of performance difference of different operation system and the LDPC code parameters on the performance of the system. (2) the design of new satellite fading channel model. The weighted sine and the design of channel simulator, the derivation process and parameters are given in this paper. The channel model of the model proposed in this paper can describe the satellite communication channel contains a variety of fading, and the solution the problem of the traditional model to channel statistics analysis. The simulation results show that the channel model in this paper the design of the two order statistics and the measured data are very similar. (3) presented a suitable satellite fading channel encoding scheme to solve the channel state collaboration. Traditional satellite cooperative communication system changes lead to poor performance the problem is introduced. The hybrid automatic retransmission request in three node satellite cooperative communication system (7) HARQ (8) protocol. To HARQ-II mechanism, is a copy of retransmission and incremental retransmission party The receiving end of the maximum transmission rate and system outage probability. By comparison, duplicate retransmission scheme has a better performance. In cooperative communication satellite retransmission scheme and HARQ will copy rate compatible LDPC code combined with the design of a rate adaptive changes of satellite communication protocol. In this protocol, and according to the relay satellite the channel changes determine the retransmission rate, growth rate of the nonlinear system is derived, and compared the performance of outage probability and throughput of satellite communication system under the agreement. That agreement with the simulation results in this paper the traditional retransmission mechanism and BER performance, direct transmission mode, regardless of the satellite fading channel, this paper the protocol can reduce the BER and outage probability.

【学位授予单位】：华侨大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN927

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