深空通信中SPINAL码的应用研究
发布时间：2018-08-22 16:47
【摘要】：深空通信传输距离远,空间节点间隔跨度大,导致传输链路损耗大、信号衰减严重,信道传输能力有限。为了保证深空通信系统的传输能力,必须采用高增益的信道编码技术,因而,性能优良的信道编译码技术一直是深空通信的重点研究方向之一。目前广泛应用于深空通信的信道编码是以Turbo码和LDPC码为代表的系列先进编码技术,但这些固定速率码通常难以适应具有复杂时变和大损耗特性的深空信道。Spinal码是2012年新提出的一种在BSC、AWGN上均能实现近容量限传输的无速率码。在地面移动通信场景中,Spinal码相比传统的高增益固定速率编码(如LDPC码)、以及无速率编码中改进的Raptor码、Strider码等编码算法,在极宽的信噪比范围内均能获得更好的性能。Spinal码的高增益、低复杂度、无固定码率等特点显示出其应用于深空通信的巨大潜力,而深空场景相对地面移动通信场景的独有特性致使Spinal码在深空中的应用仍有诸多方面需要进行深入研究。本文针对Spinal码在深空通信系统中的应用,深入地研究了适合深空信道的Spinal码的编译码参数组合、星座映射调制方式以及不同信道工作模式的选择等问题。本文首先简要地介绍和分析了深空中传统编译码技术与无速率编码的研究现状与特点,阐述了Spinal码的编译码原理、通过与传统的深空信道编码LDPC码进行性能对比,分析了Spinal码应用于深空通信系统的优势。在此基础上,深入考察了Spinal码采用不同的编解码参数对时间复杂度和性能的影响,并据此给出了适合深空场景的Spinal码参数优化建议。然后,结合深空通信对频谱效率的高要求和深空信道的非线性特点,研究了与Spinal码相匹配的调制方式,重点对比研究了Spinal码采用16-APSK、16-QAM、16-PSK三种调制的性能,给出了与Spinal码相匹配的调制方式建议。最后,由于Spinal码既可应用于模拟信道,也可应用于数字信道,对比研究了Spinal码在模拟信道和数字信道下硬解调与软解调的性能,并给出了工作模式建议。对于数字信道工作模式下Spinal码对软信息的应用,本文提出了适用于Spinal码译码时高效运用软解调生成的软信息的具体设计步骤。研究结果表明,Spinal码显示出极大的深空通信应用前景:采用256、512 bits的短码长设计,配合以16-APSK调制的Spinal码,在模拟信道工作模式下,译码性能远优于传统所采用的复杂度极高的LDPC码,在不同的信噪比条件下均能获得逼近Shannon限的性能,以信噪比为4 d B时为例,Spinal码所能达到的码率比LDPC码高了0.446 bits/symbol。
[Abstract]:The transmission distance of deep space communication is long and the span of space nodes is long, which leads to the large loss of transmission link, the serious attenuation of signal, and the limited transmission capacity of channel. In order to guarantee the transmission capability of deep space communication system, high gain channel coding technology must be adopted. Therefore, channel coding and decoding technology with good performance has been one of the key research directions of deep space communication. At present, channel coding widely used in deep space communication is a series of advanced coding techniques represented by Turbo code and LDPC code. However, these fixed-rate codes are usually difficult to adapt to the deep-space channel. Spinal codes with complex time-varying and high loss characteristics are a new non-rate code proposed in 2012, which can achieve near-capacity limited transmission on BSC-AWGN. Compared with the traditional high gain fixed rate code (such as LDPC code) and the improved Raptor code and strider code in the ground mobile communication scene, The high gain, low complexity and no fixed bit rate of the Spinal code in a wide range of signal-to-noise ratio show the great potential of its application in deep space communication. Because of the unique characteristics of the deep space scene relative to the ground mobile communication scene, the application of Spinal code in the deep air still needs to be deeply studied. Aiming at the application of Spinal codes in deep space communication systems, this paper deeply studies the encoding and decoding parameter combination of Spinal codes suitable for deep space channels, constellation mapping modulation methods and the selection of different channel working modes. Firstly, this paper briefly introduces and analyzes the research status and characteristics of traditional coding and decoding techniques and rate-free coding in deep air, expounds the encoding and decoding principle of Spinal codes, and compares the performance of LDPC codes with those of traditional deep space channel codes. The advantage of Spinal code in deep space communication system is analyzed. On this basis, the effects of different coding and decoding parameters on the time complexity and performance of Spinal codes are investigated in depth, and suggestions for optimization of Spinal code parameters suitable for deep space scenes are given. Then, considering the high requirement of spectrum efficiency in deep space communication and the nonlinear characteristics of deep space channel, the modulation mode matching with Spinal code is studied, and the performance of Spinal code using 16-APSKN 16-QAM 16-PSK modulation is compared. The modulation mode matching with Spinal code is given. Finally, because Spinal codes can be used in both analog and digital channels, the performance of hard demodulation and soft demodulation of Spinal codes in analog channel and digital channel are compared and studied, and the working mode suggestions are given. For the application of Spinal codes to soft information in the working mode of digital channels, this paper presents the specific design steps of the soft information generated by the efficient use of soft demodulation in the decoding of Spinal codes. The results show that the Spinal code shows a great prospect of application in deep space communication. With the short code length design of 256512 bits and the Spinal code modulated by 16-APSK, the decoding performance is much better than that of the traditional LDPC code in the operating mode of analog channel. The performance of approaching the Shannon limit can be obtained under different SNR conditions. Taking the signal to noise ratio (SNR) of 4 dB as an example, the code rate of Spinal code is 0.446 bit / symbol higher than that of LDPC code.
【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】：TN911.22;TN927.3
本文编号：2197722
[Abstract]:The transmission distance of deep space communication is long and the span of space nodes is long, which leads to the large loss of transmission link, the serious attenuation of signal, and the limited transmission capacity of channel. In order to guarantee the transmission capability of deep space communication system, high gain channel coding technology must be adopted. Therefore, channel coding and decoding technology with good performance has been one of the key research directions of deep space communication. At present, channel coding widely used in deep space communication is a series of advanced coding techniques represented by Turbo code and LDPC code. However, these fixed-rate codes are usually difficult to adapt to the deep-space channel. Spinal codes with complex time-varying and high loss characteristics are a new non-rate code proposed in 2012, which can achieve near-capacity limited transmission on BSC-AWGN. Compared with the traditional high gain fixed rate code (such as LDPC code) and the improved Raptor code and strider code in the ground mobile communication scene, The high gain, low complexity and no fixed bit rate of the Spinal code in a wide range of signal-to-noise ratio show the great potential of its application in deep space communication. Because of the unique characteristics of the deep space scene relative to the ground mobile communication scene, the application of Spinal code in the deep air still needs to be deeply studied. Aiming at the application of Spinal codes in deep space communication systems, this paper deeply studies the encoding and decoding parameter combination of Spinal codes suitable for deep space channels, constellation mapping modulation methods and the selection of different channel working modes. Firstly, this paper briefly introduces and analyzes the research status and characteristics of traditional coding and decoding techniques and rate-free coding in deep air, expounds the encoding and decoding principle of Spinal codes, and compares the performance of LDPC codes with those of traditional deep space channel codes. The advantage of Spinal code in deep space communication system is analyzed. On this basis, the effects of different coding and decoding parameters on the time complexity and performance of Spinal codes are investigated in depth, and suggestions for optimization of Spinal code parameters suitable for deep space scenes are given. Then, considering the high requirement of spectrum efficiency in deep space communication and the nonlinear characteristics of deep space channel, the modulation mode matching with Spinal code is studied, and the performance of Spinal code using 16-APSKN 16-QAM 16-PSK modulation is compared. The modulation mode matching with Spinal code is given. Finally, because Spinal codes can be used in both analog and digital channels, the performance of hard demodulation and soft demodulation of Spinal codes in analog channel and digital channel are compared and studied, and the working mode suggestions are given. For the application of Spinal codes to soft information in the working mode of digital channels, this paper presents the specific design steps of the soft information generated by the efficient use of soft demodulation in the decoding of Spinal codes. The results show that the Spinal code shows a great prospect of application in deep space communication. With the short code length design of 256512 bits and the Spinal code modulated by 16-APSK, the decoding performance is much better than that of the traditional LDPC code in the operating mode of analog channel. The performance of approaching the Shannon limit can be obtained under different SNR conditions. Taking the signal to noise ratio (SNR) of 4 dB as an example, the code rate of Spinal code is 0.446 bit / symbol higher than that of LDPC code.
【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】：TN911.22;TN927.3
【参考文献】
相关期刊论文 前1条
1 张乃通;李晖;张钦宇;;深空探测通信技术发展趋势及思考[J];宇航学报;2007年04期
，本文编号：2197722
本文链接：https://www.wllwen.com/kejilunwen/wltx/2197722.html
