本文選題：均衡器　切入點(diǎn)：單載波系統(tǒng)　出處：《東南大學(xué)》2015年碩士論文

【摘要】：無線通信信道的多徑效應(yīng)會引起碼間干擾現(xiàn)象,進(jìn)而影響通信質(zhì)量,解決該問題的一個重要方法是均衡器。本文研究了單載波通信系統(tǒng)中的均衡器設(shè)計,包括時域最小均方誤差準(zhǔn)則均衡算法,頻域塊迭代判決反饋均衡算法和時頻混合判決反饋均衡算法等,同時還針對室內(nèi)可見光通信和對流層散射通信這兩個應(yīng)用場景,設(shè)計了相應(yīng)的硬件系統(tǒng)。室內(nèi)可見光通信技術(shù)將發(fā)光二極管(Light Emitting Diode, LED)發(fā)出的光作為信息傳播的載體進(jìn)行通信,該技術(shù)被稱為“Lifi”,極有可能為室內(nèi)短距離通信提供全新的解決方案。而對流層散射通信則是利用大氣層中對流層對電磁波的散射實(shí)現(xiàn)遠(yuǎn)距離的非視距通信,常用于軍事通信。針對室內(nèi)可見光通信應(yīng)用場景,本文建立了多徑抽頭時延信道模型并通過測量得到信道系數(shù),給出了信道的時域沖激響應(yīng)曲線和幅頻響應(yīng)曲線。針對散射通信系統(tǒng)應(yīng)用場景,通過信道特性分析和文獻(xiàn)查閱,本文建立了時延功率譜大小呈指數(shù)衰減的瑞利衰落信道模型。均衡器在單載波通信系統(tǒng)中不可或缺的部分,本文從算法原理入手,介紹了時域最小均方誤差均衡算法(Time Domain Minimum Mean Square Error Equalizer, TD-MMSEE),時域判決反饋均衡算法(Time Domain Decision Feedback Equalizer, TD-DFE),頻域塊迭代判決反饋均衡算法(Frequency Domain Iterative Block Decision Feedback Equalizer, FD-IBDFE)和時頻域混合判決反饋均衡算法(Hybrid Decision Feedback Equalizer, H-DFE)的原理,并給出上述算法在可見光通信場景下和對流層散射通信場景下的誤碼率性能。結(jié)合信道特點(diǎn)和各算法的計算復(fù)雜度,本文為可見光通信設(shè)計了頻域最小均方誤差均衡系統(tǒng)接收方案,為散射通信系統(tǒng)設(shè)計了時頻混合判決反饋均衡系統(tǒng)接收方案。根據(jù)迭代接收機(jī)的迭代思想,本文提出了基于硬干擾抵消和軟干擾抵消的迭代判決反饋均衡算法。仿真結(jié)果表明,硬干擾抵消迭代判決反饋均衡算法在3/4碼率條件下能獲得0.2～0.3dB增益,在1/2碼率條件下能獲得0.7dB左右增益,而軟干擾抵消迭代判決反饋均衡算法在3/4碼率條件下能獲得0.6～0.7dB增益,在1/2碼率條件下能獲得1.2～1.3dB增益,驗(yàn)證了算法的有效性。本文最后一章給出了室內(nèi)可見光通信系統(tǒng)和對流層散射通信系統(tǒng)的硬件設(shè)計與實(shí)現(xiàn)。硬件平臺采用Xilinx公司的ML605開發(fā)板。本章從系統(tǒng)框架入手,詳細(xì)介紹了系統(tǒng)各個模塊的設(shè)計原理和主要作用,散射通信系統(tǒng)采用正交相移鍵控(Quadrature Phase Shift Keying, QPSK)調(diào)制,系統(tǒng)時鐘速率為115.2MHz,實(shí)際通信速率38.4Mbps,可見光通信的采用開關(guān)鍵控(On-Off Keying, OOK)調(diào)制,系統(tǒng)時鐘速率為200MHz,實(shí)際通信速率100Mbps,上述兩個系統(tǒng)中均可傳輸高清視頻業(yè)務(wù),驗(yàn)證了硬件設(shè)計的正確性。
[Abstract]:The multipath effect of wireless communication channel will cause inter-symbol interference (ISI) and then affect the communication quality. An important method to solve this problem is equalizer.In this paper, the design of equalizer in single carrier communication system is studied, including the equalization algorithm of time domain minimum mean square error criterion, frequency domain iterative decision feedback equalization algorithm and time-frequency mixed decision feedback equalization algorithm, etc.At the same time, a hardware system is designed for indoor visible light communication and tropospheric scattering communication.Indoor visible light communication technology uses light emitting diode (LED) as a carrier of information transmission. This technology is called "Lifi", which is likely to provide a new solution for indoor short-range communication.Tropospheric scattering communication, which is often used in military communications, uses the tropospheric scattering of electromagnetic waves in the atmosphere to realize long-range non-line-of-sight communication.In this paper, a multi-path tap time-delay channel model is established for indoor visible light communication applications. The channel coefficients are obtained by measurement, and the time-domain impulse response curves and amplitude-frequency response curves of the channel are given.In this paper, a Rayleigh fading channel model with exponential attenuation of time-delay power spectrum is established by analyzing the channel characteristics and consulting the literature for the application scene of scattering communication system.The equalizer is an indispensable part of a single carrier communication system.浠嬬粛浜嗘椂鍩熸渶灝忓潎鏂硅宸潎琛＄畻娉，

本文編號：1703748