深空通信中基于中继的网络调制技术

发布时间：2018-03-27 16:46

本文选题：网络调制技术　切入点：星座点映射　出处：《哈尔滨工业大学》2014年硕士论文

【摘要】：网络调制技术是一种根据发送信息的相对重要性而建立的保护度机制,其系统模型为基于中继的三点式网络拓扑结构。在本篇论文中,首次将网络调制技术应用于深空通信中,提出了深空通信中一种基于中继的网络调制拓扑结构,主要目的在于折中系统可靠性与有效性,即在保证一定系统可靠性的前提下,大幅度提升系统有效性。研究的主要内容包括:网络调制技术的星座映射规则、不同映射规则及不同解调方法所带来系统性能影响、衡量系统可靠性及有效性的两个重要指标:误码率以及吞吐量的计算原理及公式推导这三个方面。本文对网络调制技术的系统模型、传输机理以及星座点映射规则做了详细介绍。网络调制技术的不同星座点映射规则及不同的解调方法对系统性能影响是不同的,本文以三跳链路中某一链路采用Gray映射的8PSK网络调制技术为例,提出了整体解调法及逐位解调法,并对两种不同的解调方法进行了Matlab仿真,通过对仿真结果进行分析,得出的结论是采用逐位解调法可以降低系统误码率。对系统误码率及吞吐量的计算公式进行了推导仿真。误码率及吞吐量是系统可靠性及有效性的主要表现形式,本文提出利用递归方法推导出在加性高斯白噪声信道条件下通用分层PAM误码率公式,并对不同星座点映射规则的网络调制技术进行了Matlab仿真及结果的分析比较。对于吞吐量的求解方法,利用网络调制的传输模型,以香农第二极限定理为依据,推导出网络调制系统吞吐量的求解公式,并应用Matlab仿真对采用不同调制类型的网络调制的系统吞吐量进行了分析对比。通过仿真验证了网络调制技术应用于深空通信链路中可提升系统性能。以月地系通信链路为例,选取月地系拉格朗日L1点作为中继卫星的位置,通过Matlab仿真,把系统采用网络调制技术、直传链路调制以及单中继两跳链路调制这三种不同传输方式所得出的不同吞吐量曲线绘制在一幅图中。通过对结果分析比较可得出结论:网络调制技术应用于深空通信中可有效提升系统吞吐量,从而有效解决了深空通信中低有效性的难题。
[Abstract]:Network modulation is a protection mechanism based on the relative importance of sending information. Its system model is a three-point network topology based on relay. In this paper, the network modulation technology is applied to deep space communication for the first time. In this paper, a network modulation topology based on relay in deep space communication is proposed. The main purpose is to compromise the reliability and effectiveness of the system, that is, to ensure the reliability of a certain system. The main contents of the research include: constellation mapping rules of network modulation technology, different mapping rules and different demodulation methods bring about system performance impact. There are two important indexes to measure the reliability and effectiveness of the system: the calculation principle and formula derivation of error rate and throughput. The transmission mechanism and constellation point mapping rules are introduced in detail. Different constellation mapping rules and different demodulation methods of network modulation technology have different effects on system performance. In this paper, a 8PSK network modulation technique based on Gray mapping in a three-hop link is taken as an example. A global demodulation method and a bit-by-bit demodulation method are proposed. Two different demodulation methods are simulated by Matlab, and the simulation results are analyzed. The conclusion is that the bit by bit demodulation method can reduce the system bit error rate. The calculation formulas of the system bit error rate and throughput are deduced and simulated. The error rate and throughput are the main forms of system reliability and effectiveness. In this paper, a general hierarchical PAM BER formula for additive Gao Si white noise channel is derived by recursive method. The network modulation technology with different constellation mapping rules is simulated by Matlab and the results are analyzed and compared. The solution of throughput is based on Shannon's second limit theorem by using the transmission model of network modulation. The formula for solving the throughput of the network modulation system is derived. The throughput of network modulation with different modulation types is analyzed and compared by using Matlab simulation. It is verified by simulation that the application of network modulation technology in deep space communication link can improve the system performance. The position of lunar and terrestrial Lagrange L1 is chosen as relay satellite. The system is simulated by Matlab, and the network modulation technology is adopted. The different throughput curves obtained from three different transmission modes, direct link modulation and single relay two-hop link modulation, are drawn in a single diagram. By analyzing and comparing the results, it can be concluded that the network modulation technology is applied to the depth. In the air communication, the system throughput can be increased effectively, Thus effectively solve the problem of low effectiveness of deep space communication.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN927;TN911.3

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