本文選題：協(xié)作通信 + 量化轉(zhuǎn)發(fā)��； 參考：《杭州電子科技大學(xué)》2017年碩士論文

【摘要】：當(dāng)前,無(wú)線協(xié)作通信由于傳輸可靠、有效和覆蓋范圍廣而成為研究熱點(diǎn),但仍存在復(fù)雜度高和性能未能接近理論值等缺陷。為協(xié)助解決上述問(wèn)題,本學(xué)位論文主要開(kāi)展了中繼轉(zhuǎn)發(fā)策略優(yōu)化及編碼協(xié)作的改進(jìn)研究。首先,簡(jiǎn)介了協(xié)作通信背景、發(fā)展和現(xiàn)狀。然后,重點(diǎn)分析了現(xiàn)有無(wú)線協(xié)作通信模型、合并技術(shù)和中繼協(xié)議,并引入了鏈路自適應(yīng)再生(LAR)轉(zhuǎn)發(fā)協(xié)議。最后,重點(diǎn)探討了優(yōu)化LAR轉(zhuǎn)發(fā)協(xié)議、量化轉(zhuǎn)發(fā)(QF)及Raptor編碼協(xié)作等創(chuàng)新改進(jìn)。全文內(nèi)容和貢獻(xiàn)主要如下:1.針對(duì)譯碼轉(zhuǎn)發(fā)(DF)中繼系統(tǒng)不能獲得分集增益的問(wèn)題,引入了LAR理論分析研究。首先,研究了LAR協(xié)議的實(shí)現(xiàn)過(guò)程及低復(fù)雜度單中繼選擇方案。然后,針對(duì)單中繼系統(tǒng),推導(dǎo)了高信噪比(SNR)下誤碼率(BER)和中斷概率的近似表達(dá)式。仿真表明:LAR較放大轉(zhuǎn)發(fā)(AF)、DF和選擇譯碼轉(zhuǎn)發(fā)(SDF)在BER方面有更大優(yōu)勢(shì)。當(dāng)BER=10-3時(shí),分別有約3.5dB、7dB和7dB的SNR增益,且LAR中繼系統(tǒng)的中斷概率隨中繼個(gè)數(shù)的增加而不斷提高;2.針對(duì)現(xiàn)有QF復(fù)雜度較高的缺陷,提出了低復(fù)雜度QF方案。其采用了低階量化和調(diào)制,使復(fù)雜度有較大降低。在目的節(jié)點(diǎn),其將量化信息和直傳信息最大比合并(MRC),可降低系統(tǒng)BER。同時(shí),利用中繼選擇和功率分配技術(shù)進(jìn)一步優(yōu)化該方案。最后,仿真分析了1-bit、2-bit和3-bit QF的BER性能。結(jié)果表明:當(dāng)BER=10-2,3-bit QF方案較1-bit、2-bit QF分別有約4.5~7.5dB和1~2.5dB的SNR增益;當(dāng)中繼距離目的節(jié)點(diǎn)較近時(shí),所提QF協(xié)議具有較好BER性能。在等功率分配方案下,對(duì)于2-bit QF,在BER為10-3處,當(dāng)源-中繼鏈路歸一化距離為0.9時(shí),較0.7、0.5、0.3和0.1情況分別有約5dB、7.5dB、9dB和15dB的SNR增益。另外,相對(duì)于等功率分配方案,優(yōu)化功率分配系統(tǒng)平均有約2.5dB功率增益;3.針對(duì)無(wú)線協(xié)作通信系統(tǒng)的信道狀態(tài)信息(CSI)難以準(zhǔn)確估算問(wèn)題,利用噴泉碼的無(wú)碼率特性,提出了Raptor編碼協(xié)作(CC)方案。在該方案中,源和中繼節(jié)點(diǎn)使用不同Raptor編碼,目的節(jié)點(diǎn)接收不同來(lái)源獨(dú)立消息后,根據(jù)碼字間關(guān)系聯(lián)合譯碼,可在高SNR下獲得較大編碼增益和滿分集效果。為了降低復(fù)雜度,Raptor預(yù)編碼采用了整數(shù)序列構(gòu)造的準(zhǔn)循環(huán)低密度奇偶校驗(yàn)(QC-LDPC)碼,獲得了較低的線性預(yù)編碼復(fù)雜度。仿真表明:在BER為10-4時(shí),所提Raptor編碼協(xié)作方案較傳統(tǒng)DF協(xié)議Raptor方案、Raptor與分布式空時(shí)分組碼(DSTBC)結(jié)合方案,分別有約2dB和1dB的SNR增益。而且,當(dāng)中斷概率為10-2時(shí),其SNR增益較CC、DF提高了約2dB和7dB。本文通過(guò)對(duì)協(xié)作中繼轉(zhuǎn)發(fā)策略和編碼協(xié)作的優(yōu)化改進(jìn),可較好地改善協(xié)作通信系統(tǒng)性能。所提改進(jìn)點(diǎn)也均以低復(fù)雜度模式實(shí)現(xiàn),便于工程實(shí)踐,具備較高實(shí)用價(jià)值。
[Abstract]:At present, wireless cooperative communication has become a research hotspot because of its reliable transmission, effective and wide coverage, but there are still high complexity and failure to approach the theoretical value. In order to help solve the above problems, this dissertation mainly carried out the research on the optimization of relay forwarding strategy and coding cooperation. First, the collaborative communication back was briefly introduced. The current wireless cooperative communication model, merging technology and relay protocol are analyzed, and link adaptive regeneration (LAR) forwarding protocol is introduced. Finally, the optimization of LAR forwarding protocol, quantitative forwarding (QF) and Raptor coding cooperation are discussed. The content and contribution of the full text are as follows: 1. The DF relay system can not obtain diversity gain, and introduces the LAR theoretical analysis. First, the realization process of the LAR protocol and the single relay selection scheme with low complexity are studied. Then, the approximate expression of the bit error rate (BER) and the interrupt probability under the high signal to noise ratio (SNR) is derived for the single relay system. The simulation shows that LAR is more magnified. AF, DF and selective decoding forward (SDF) have a greater advantage in BER. When BER=10-3, there are SNR gains of about 3.5dB, 7dB and 7dB, and the interrupt probability of the LAR relay system increases with the increase of the number of relay. 2., a low complexity QF scheme is proposed for the existing QF complexity. Low order quantization and modulation are adopted. The complexity is greatly reduced. In the destination node, it combines the maximum ratio of quantized information and direct transmission information (MRC), reduces system BER. and optimizes the scheme by using relay selection and power allocation technology. Finally, the simulation analysis of the BER properties of 1-bit, 2-bit and 3-bit QF shows that BER=10-2,3-bit QF scheme is more than 1-bit, 2-bit QF has a SNR gain of about 4.5~7.5dB and 1~2.5dB respectively; when the relay distance is closer, the proposed QF protocol has a better BER performance. In the equal power allocation scheme, the 2-bit QF is 10-3 at BER, and when the source relay link normalization distance is 0.9, the 0.7,0.5,0.3 and 0.1 are about 5dB, 7.5dB, and gain gain. In addition, the optimal power allocation system has an average 2.5dB power gain relative to the equal power allocation scheme, and 3. is difficult to accurately estimate the channel state information (CSI) for the wireless cooperative communication system. The Raptor coding cooperation (CC) scheme is proposed by using the fountain code's non bit rate characteristics. In this scheme, the source and relay nodes use different Raptor compacts. In order to reduce the complexity, the Raptor precoding uses an integer sequence constructed quasi cyclic low density parity check (QC-LDPC) code to reduce the complexity. In order to reduce the complexity, the complexity of the Linear Precoding is obtained. The complexity of the low Linear Precoding is obtained. It is true that when BER is 10-4, the proposed Raptor coding scheme has a SNR gain of about 2dB and 1dB, compared with the traditional DF protocol Raptor scheme, Raptor and distributed space time block code (DSTBC). Moreover, when the interrupt probability is 10-2, the SNR gain of the SNR is CC. The optimization and improvement of cooperation can better improve the performance of the cooperative communication system. The proposed improvement points are also implemented in a low complexity mode, which is convenient for engineering practice and has high practical value.

【學(xué)位授予單位】：杭州電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TN92

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本文編號(hào)：1842500