基于LDPC码的飞行器组网自适应编码调制技术研究

发布时间：2018-03-11 23:00

本文选题：飞行器组网　切入点：信道模型　出处：《哈尔滨工业大学》2014年硕士论文　论文类型：学位论文

【摘要】：飞行器协同执行任务的需求越来越迫切，因此飞行器组网通信的相关问题亟待解决。飞行器组网通信时，信道条件复杂，同时存在大、小尺度衰落，固定的编码调制方式在保证通信质量的情况下难以高效利用频谱资源。自适应编码调制（ACM）技术是一种兼顾通信可靠性和有效性的先进技术。本课题研究了基于LDPC码的飞行器组网ACM技术，是一种适应飞行器组网通信复杂信道情况下的重要支撑技术。首先，对于飞行器组网ACM技术中的LDPC信道编码进行研究，概述了LDPC码的相关理论，，并深入研究了LDPC码的构造和译码，结合高阶的调制方式对于不同码率下的LDPC码性能进行仿真研究，分析了各种调制方式和码率结合的情况下LDPC码的误码率性能，为飞行器组网ACM系统提供了可选的编码和调制模式组合。然后，就飞行器组网通信的信道模型进行了深入研究，分析了飞行器编队内的通信信道和飞行器编队与地面站之间的通信信道，并就两种信道分别进行了链路核算，在链路核算的基础之上建立信道时间序列模型，为ACM技术研究做了信道方面的研究基础。再后，基于LDPC码设计了飞行器组网ACM技术的总体方案，包括信道编译码、调制解调、信道估计和自适应编码码率和调制方式控制；对于基于LDPC的ACM可选模式进行了设计，确定了5种可转换模式，同时还研究了M2M4和DA-ML信道估计技术；在研究和分析门限移位法的基础之上，提出了改进的ACM门限切换法——施密特式ACM门限切换法。最后，通过仿真研究，得出施密特式ACM门限切换法具有良好的性能，在减少频繁切换和提高误码率等方面的性能均有提升。
[Abstract]:The need for collaborative mission implementation is becoming more and more urgent, so the related problems of aircraft networking communication need to be solved. When aircraft network communication, the channel conditions are complex, and there are large and small scale fading at the same time. It is difficult to utilize spectrum resource efficiently in the case of fixed coding modulation. Adaptive coded modulation (ACM) is an advanced technology which takes into account the reliability and effectiveness of communication. This paper studies the technology based on LDPC. Code based ACM technology for aircraft networking, It is an important supporting technique for complex communication channels. First of all, the LDPC channel coding in the ACM technology of aircraft network is studied, and the theory of LDPC codes is summarized, and the construction and decoding of LDPC codes are deeply studied. The performance of LDPC codes at different bit rates is simulated with high-order modulation, and the BER performance of LDPC codes with different modulation modes and bit rates is analyzed. This paper provides an optional combination of coding and modulation modes for the ACM system of aircraft networking. Then, the channel model of aircraft networking communication is studied in depth. The communication channel in aircraft formation and the communication channel between aircraft formation and ground station are analyzed. The channel time series model is established on the basis of link accounting. After that, the overall scheme of vehicle network ACM technology is designed based on LDPC code, including channel coding and decoding, modulation and demodulation, channel estimation, adaptive coding rate and modulation mode control. The ACM optional mode based on LDPC is designed, five convertible modes are determined, and M2M4 and DA-ML channel estimation techniques are also studied, which are based on the study and analysis of threshold shift method. An improved ACM threshold switching method, Schmitt ACM threshold switching method, is proposed. Finally, through simulation research, it is concluded that Schmitt ACM threshold switching method has good performance. The performance in reducing frequent handoff and increasing bit error rate has been improved.
【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】：TN911.3

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