深空通信中SPINAL碼的應(yīng)用研究
發(fā)布時間：2018-08-22 16:47
【摘要】：深空通信傳輸距離遠,空間節(jié)點間隔跨度大,導(dǎo)致傳輸鏈路損耗大、信號衰減嚴(yán)重,信道傳輸能力有限。為了保證深空通信系統(tǒng)的傳輸能力,必須采用高增益的信道編碼技術(shù),因而,性能優(yōu)良的信道編譯碼技術(shù)一直是深空通信的重點研究方向之一。目前廣泛應(yīng)用于深空通信的信道編碼是以Turbo碼和LDPC碼為代表的系列先進編碼技術(shù),但這些固定速率碼通常難以適應(yīng)具有復(fù)雜時變和大損耗特性的深空信道。Spinal碼是2012年新提出的一種在BSC、AWGN上均能實現(xiàn)近容量限傳輸?shù)臒o速率碼。在地面移動通信場景中,Spinal碼相比傳統(tǒng)的高增益固定速率編碼(如LDPC碼)、以及無速率編碼中改進的Raptor碼、Strider碼等編碼算法,在極寬的信噪比范圍內(nèi)均能獲得更好的性能。Spinal碼的高增益、低復(fù)雜度、無固定碼率等特點顯示出其應(yīng)用于深空通信的巨大潛力,而深空場景相對地面移動通信場景的獨有特性致使Spinal碼在深空中的應(yīng)用仍有諸多方面需要進行深入研究。本文針對Spinal碼在深空通信系統(tǒng)中的應(yīng)用,深入地研究了適合深空信道的Spinal碼的編譯碼參數(shù)組合、星座映射調(diào)制方式以及不同信道工作模式的選擇等問題。本文首先簡要地介紹和分析了深空中傳統(tǒng)編譯碼技術(shù)與無速率編碼的研究現(xiàn)狀與特點,闡述了Spinal碼的編譯碼原理、通過與傳統(tǒng)的深空信道編碼LDPC碼進行性能對比,分析了Spinal碼應(yīng)用于深空通信系統(tǒng)的優(yōu)勢。在此基礎(chǔ)上,深入考察了Spinal碼采用不同的編解碼參數(shù)對時間復(fù)雜度和性能的影響,并據(jù)此給出了適合深空場景的Spinal碼參數(shù)優(yōu)化建議。然后,結(jié)合深空通信對頻譜效率的高要求和深空信道的非線性特點,研究了與Spinal碼相匹配的調(diào)制方式,重點對比研究了Spinal碼采用16-APSK、16-QAM、16-PSK三種調(diào)制的性能,給出了與Spinal碼相匹配的調(diào)制方式建議。最后,由于Spinal碼既可應(yīng)用于模擬信道,也可應(yīng)用于數(shù)字信道,對比研究了Spinal碼在模擬信道和數(shù)字信道下硬解調(diào)與軟解調(diào)的性能,并給出了工作模式建議。對于數(shù)字信道工作模式下Spinal碼對軟信息的應(yīng)用,本文提出了適用于Spinal碼譯碼時高效運用軟解調(diào)生成的軟信息的具體設(shè)計步驟。研究結(jié)果表明,Spinal碼顯示出極大的深空通信應(yīng)用前景:采用256、512 bits的短碼長設(shè)計,配合以16-APSK調(diào)制的Spinal碼,在模擬信道工作模式下,譯碼性能遠優(yōu)于傳統(tǒng)所采用的復(fù)雜度極高的LDPC碼,在不同的信噪比條件下均能獲得逼近Shannon限的性能,以信噪比為4 d B時為例,Spinal碼所能達到的碼率比LDPC碼高了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.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN911.22;TN927.3
本文編號：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.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN911.22;TN927.3
【參考文獻】
相關(guān)期刊論文 前1條
1 張乃通;李暉;張欽宇;;深空探測通信技術(shù)發(fā)展趨勢及思考[J];宇航學(xué)報;2007年04期
，本文編號：2197722
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