【摘要】：摘要：比特交織編碼調(diào)制(BICM)是一種典型的編碼調(diào)制技術(shù),它結(jié)構(gòu)簡單、性能優(yōu)異,意在增加編碼的多樣性,針對TCM靈活性差和在衰落信道中性能差的缺點(diǎn),在理想交織時(shí)將編碼器和調(diào)制器分離設(shè)計(jì),具有高度的靈活性,并可以在衰落信道具有很好的魯棒性。自從上世紀(jì)末被提出以來,BICM一直是編碼調(diào)制領(lǐng)域中的熱點(diǎn)之一。目前已經(jīng)被廣泛應(yīng)用在各商用無線通信系統(tǒng)中,在未來的光通信領(lǐng)域可能也會(huì)實(shí)現(xiàn)大規(guī)模的應(yīng)用。但是,它仍存在一些新的技術(shù)難點(diǎn),已知的最優(yōu)星座映射并不能適應(yīng)高頻譜效率且非規(guī)則最優(yōu)多維星座映射方式并未給出�；谙冗M(jìn)編解碼技術(shù)(LDPC、Turbo)的BICM系統(tǒng)在光通信中的應(yīng)用研究也越來越受關(guān)注,對它的研究有重大的理論意義和實(shí)際意義。 本文針對不同的信道類型對已知的多維星座映射進(jìn)行優(yōu)化并從信道容量的角度對其進(jìn)行仿真分析,同時(shí)也對基于LDPC碼的BICM系統(tǒng)(LDPC-BICM系統(tǒng))在光纖通信系統(tǒng)中的一些問題進(jìn)行了研究。主要的工作內(nèi)容有以下幾點(diǎn)： 1.本文先回顧了BICM的基本理論框架。從最優(yōu)標(biāo)識的設(shè)計(jì)優(yōu)化出發(fā),研究并編寫二進(jìn)制交換算法(BSA),針對AWGN信道和Rayleigh信道運(yùn)用相應(yīng)的基于星座距離譜的代價(jià)函數(shù)對已知的多維星座映射進(jìn)行優(yōu)化并給出多種已優(yōu)化的搜索結(jié)果及相應(yīng)的代價(jià)函數(shù)值。 2.本文進(jìn)一步從理想先驗(yàn)信息和無先驗(yàn)信息兩種情況考慮,對所得優(yōu)化多維星座映射下的BICM系統(tǒng)在AWGN信道和Rayleigh信道中容量分別進(jìn)行仿真,并通過與傳統(tǒng)MQAM星座映射下的容量進(jìn)行對比,意在獲得更好的系統(tǒng)漸進(jìn)性能。另外針對AWGN信道從信道容量出發(fā)進(jìn)一步分析了同一維數(shù)下EsNo對優(yōu)化結(jié)果影響。 3.最后,從殘余色散和非線性相位噪聲的角度對LDPC-BICM系統(tǒng)在光通信的性能進(jìn)行了研究。通過建立不同的光纖信道模型并簡化成相應(yīng)公式,通過matlab-CML工具對LDPC-BICM系統(tǒng)在光通信中的性能進(jìn)行仿真并對其殘余色散和非線性相位噪聲的容忍度進(jìn)行分析。仿真中采用碼長為16200,碼率為1/4的標(biāo)準(zhǔn)DVB-S2-LDPC碼和軟輸出解調(diào)算法(Max-Log-MAP),映射方式均為16QAM-Gray映射。
[Abstract]:Abstract: bit interleaved coded modulation (BICM) is a typical coding and modulation technique. It is simple in structure and excellent in performance. It is intended to increase the diversity of coding. In view of the disadvantage of TCM flexibility and low neutral energy in fading channels, it is designed to separate the encoder from the modulator in ideal interleaving, with high flexibility and can be used in fading messages. The props have good robustness. Since the end of the last century, BICM has been one of the hotspots in the field of coding and modulation. It has been widely used in commercial wireless communication systems and may also be used in the field of optical communication in the future. However, there are still some new technical difficulties, the best known stars are known. The seat mapping does not adapt to the high frequency spectrum efficiency and the irregular optimal multidimensional constellation mapping method has not been given. The application of BICM system based on advanced codec (LDPC, Turbo) in optical communication is becoming more and more concerned. It has great theoretical and practical significance for its research.
This paper optimizes the known multidimensional constellation mapping for different channel types and simulates it from the angle of channel capacity, and studies some problems in the optical fiber communication system based on the LDPC code based BICM system (LDPC-BICM system). The main work content has the following points:
1. this paper first reviews the basic theoretical framework of BICM. From the optimization of the optimal logo design, we study and write the binary exchange algorithm (BSA), and optimize the known multidimensional constellation mapping for the AWGN channel and the Rayleigh channel based on the corresponding cost function based on the constellation distance spectrum, and give a variety of optimized search results and corresponding results. The value of the cost function.
2. considering the two conditions of ideal prior information and no prior information, this paper simulates the capacity of the BICM system in the AWGN channel and the Rayleigh channel under the multi-dimensional constellation mapping, and compares it with the capacity of the traditional MQAM constellation, so as to obtain better system progressive performance. In addition, the AWGN system is aimed at AWGN. From the channel capacity, the channel further analyzes the influence of EsNo on the optimization result under the same dimension.
3. finally, the performance of LDPC-BICM system in optical communication is studied from the angle of residual dispersion and nonlinear phase noise. By establishing different optical fiber channel models and simplifying the corresponding formula, the performance of LDPC-BICM system in optical communication is simulated by matlab-CML tool, and its residual dispersion and nonlinear phase noise are made. The tolerance is analyzed. In the simulation, the standard DVB-S2-LDPC code and the soft output demodulation algorithm (Max-Log-MAP) with code length of 16200, the rate of 1/4 and the soft output demodulation algorithm (Max-Log-MAP) are all mapped.
【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN929.1

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本文編號：2151135