本文關(guān)鍵詞：極化碼及其與MBM級(jí)聯(lián)技術(shù)研究　出處：《浙江大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 極化碼 SCL譯碼算法 MBM技術(shù) 級(jí)聯(lián)系統(tǒng) 低復(fù)雜度ML檢測(cè)

【摘要】：信道編碼是無(wú)線通信系統(tǒng)中對(duì)抗干擾和衰落不可或缺的技術(shù)手段。極化碼是最新提出的一種理論上能達(dá)到香農(nóng)極限的信道編碼,編碼和譯碼復(fù)雜度低,具有廣泛的應(yīng)用前景。MBM(Media-Based Modulation)是一種新型的調(diào)制傳輸技術(shù),它將部分信息承載到信道狀態(tài)上,從而提高數(shù)據(jù)傳輸效率和物理層安全性。將極化碼和MBM級(jí)聯(lián),能夠以較低的復(fù)雜度提升系統(tǒng)性能。本文主要研究了極化碼的譯碼算法、極化碼與MBM級(jí)聯(lián)方案以及級(jí)聯(lián)系統(tǒng)的檢測(cè)譯碼技術(shù)。本文首先詳細(xì)介紹了極化碼和MBM的原理特性。本文詳細(xì)闡述了極化碼的極化現(xiàn)象和原理,引進(jìn)密度進(jìn)化和高斯近似方法來(lái)度量信道可靠性。然后對(duì)極化碼的編譯碼算法進(jìn)行 了說(shuō)明,并對(duì) SC(SuccessiveCancellation)和 BP(BeliefPropagation)譯碼算法做了仿真性能對(duì)比。針對(duì)MBM技術(shù),本文將MBM應(yīng)用到MIMO(Multiple-Input Multiple-Output)系統(tǒng)中,并對(duì)相同數(shù)據(jù)速率下不同多天線技術(shù)方案進(jìn)行了性能比較。然后本文對(duì)極化碼譯碼算法進(jìn)行了研究,提出了改進(jìn)的雙閾值剪枝策略和動(dòng)態(tài)路徑拓展的SCL(SC List)算法。在原來(lái)雙閾值剪枝策略的基礎(chǔ)上,提出了新的閾值劃分方法。新策略將選取路徑度量值過(guò)程的復(fù)雜度從O(LogL)降低為O(L)。利用分支策略和剪枝策略,本文提出了一種動(dòng)態(tài)路徑拓展的SCL算法,簡(jiǎn)稱DPE-SCL(Dynamic Path Extention SCL)算法。這種譯碼算法不固定候選路徑數(shù),允許其動(dòng)態(tài)變化,由分治策略和剪枝策略來(lái)控制路徑數(shù)的變化。仿真結(jié)果表明,DPE-SCL算法在低信噪比下有更好的性能,但是以路徑數(shù)增多為代價(jià),對(duì)應(yīng)地,高信噪比下性能略有下降,此時(shí)具有較低的譯碼復(fù)雜度。最后研究了極化碼與MBM的級(jí)聯(lián)方案。本文利用極化碼與MBM各自的特點(diǎn),提出了一種新的級(jí)聯(lián)方式,稱為PC-MBM(Polar Coded MBM)。它將極化碼的固定位比特映射到信道序號(hào)MBM消息上,而將信息位比特映射到SBM(Source-Based Modultaion)消息上。由于固定位比特已知,在接收端就不必對(duì)信道序號(hào)進(jìn)行估計(jì),直接可以用于SBM消息的檢測(cè),檢測(cè)復(fù)雜度大幅下降。接著利用信道極化特性,將PC-MBM信道轉(zhuǎn)化為并行獨(dú)立的子信道,根據(jù)子信道的信道容量來(lái)進(jìn)行極化碼編碼構(gòu)造。針對(duì)級(jí)聯(lián)系統(tǒng)的檢測(cè)譯碼,本文基于軟判決ML檢測(cè)算法,提出了兩種低復(fù)雜度的ML(Maximum Likelihood)檢測(cè)方法。首先借鑒球形譯碼的思路,將搜索空間限定在一定范圍內(nèi)。其次,提出了區(qū)域限制的ML檢測(cè)方法,將搜索空間進(jìn)一步減小,使得計(jì)算復(fù)雜度更低。
[Abstract]:Channel coding is an indispensable technique for anti-jamming and fading in wireless communication systems. Polarization code is a newly proposed channel coding which can reach Shannon limit theoretically. The complexity of coding and decoding is low. MBMN Media-Based Modulation is a new modulation and transmission technology, which carries some information to the channel state. In order to improve the data transmission efficiency and physical layer security, polarization code and MBM concatenation can improve the system performance with low complexity. This paper mainly studies the decoding algorithm of polarization code. The scheme of polarization code concatenation with MBM and the detection and decoding technology of concatenated system. Firstly, the principle and characteristics of polarization code and MBM are introduced in detail. The polarization phenomenon and principle of polarization code are described in detail in this paper. Density evolution and Gao Si approximation are introduced to measure channel reliability. And BPU Beliefpagation). The simulation performance of the decoding algorithm is compared. Aiming at the MBM technology. In this paper, MBM is applied to the MIMO(Multiple-Input Multiple-Output system. The performance of different multi-antenna schemes at the same data rate is compared. Then the decoding algorithm of polarimetric codes is studied in this paper. An improved two-threshold pruning strategy and a dynamic path extension (SCL(SC list) algorithm are proposed, based on the original two-threshold pruning strategy. A new threshold partition method is proposed, which reduces the complexity of the process of selecting path weights from OGlogL to OFL, and makes use of branching strategy and pruning strategy. In this paper, a dynamic path extension SCL algorithm is proposed. Short for DPE-SCL(Dynamic Path Extention SCL, this decoding algorithm does not fix the number of candidate paths, allowing it to change dynamically. The simulation results show that the algorithm has better performance under low SNR, but at the cost of increasing the number of paths. At the same time, the decoding complexity is low. Finally, the concatenation scheme of polarization code and MBM is studied. In this paper, the characteristics of polarization code and MBM are utilized. In this paper, a new concatenation method, called PC-MBM(Polar Coded MMP, is proposed, which maps the fixed bit bits of the polarization code to the MBM message with the serial number of the channel. The information bits are mapped to the SBM(Source-Based module on the message. Because the fixed bit bits are known, it is not necessary to estimate the serial number of the channel at the receiving end. It can be directly used in the detection of SBM messages, and the detection complexity is greatly reduced. Then, the PC-MBM channel is transformed into a parallel independent sub-channel by using the polarization characteristics of the channel. Polarization code coding is constructed according to the channel capacity of subchannels. For the detection and decoding of cascaded systems, this paper is based on soft decision ML detection algorithm. Two low complexity ML(Maximum likelihood-based detection methods are proposed. Firstly, the search space is limited to a certain range by using the idea of spherical decoding. An area limited ML detection method is proposed to further reduce the search space and reduce the computational complexity.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TN911.22
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本文編號(hào)：1421066