發(fā)布時(shí)間：2018-04-13 05:13

  本文選題：快時(shí)變衰落 + 頻域均衡系統(tǒng)��； 參考：《浙江工業(yè)大學(xué)》2014年碩士論文

【摘要】：移動(dòng)寬帶無(wú)線通信系統(tǒng)通常需要應(yīng)對(duì)快速時(shí)變衰落環(huán)境下有限頻譜帶寬的信道時(shí)頻雙選擇性引起的干擾問(wèn)題。因此,帶寬受限的雙選擇性信道中抑制干擾的均衡算法研究意義重大。雖然多載波傳輸,如正交頻分復(fù)用(OFDM)技術(shù),在補(bǔ)償雙選擇性信道有其特殊的優(yōu)勢(shì)且研究成果成熟,但是其中存在的高峰均比、相位噪聲敏感度高等問(wèn)題不利于實(shí)際應(yīng)用。單載波頻域均衡(SC-FDE)相比于OFDM來(lái)說(shuō),峰均比低且具有相近的抗多徑性能,因此,近10年來(lái)在寬帶無(wú)線通信的研究中受到了廣泛關(guān)注。但是其比特流時(shí)域調(diào)制解調(diào)的特性使得其在快時(shí)變衰落環(huán)境中抗干擾的研究和OFDM系統(tǒng)有所不同。鑒于此,文本開(kāi)展了對(duì)快時(shí)變衰落環(huán)境中SC-FDE系統(tǒng)干擾抑制問(wèn)題的研究。本文通過(guò)對(duì)壓縮脈沖響應(yīng)濾波器(SIRF)的算法研究與設(shè)計(jì),在有限長(zhǎng)循環(huán)前綴(CP)條件下,抑制SC-FDE系統(tǒng)中的干擾以達(dá)到降低誤碼率的同時(shí)保持系統(tǒng)頻譜效率。本文的主要工作包括了MSSNR-SIRF的改進(jìn)算法,以及通過(guò)理論推導(dǎo)獲得快時(shí)變衰落信道中抑制干擾的SIRF最佳性能參數(shù)設(shè)計(jì)方案。同時(shí),利用等效噪聲近似估計(jì)對(duì)最佳SIRF下最小均方誤差準(zhǔn)則(MMSE)頻域均衡器進(jìn)行了改進(jìn),在一定程度上抑制了噪聲干擾。本文的主要結(jié)構(gòu)分為四個(gè)部分。首先,本文分析了快時(shí)變衰落中信道的特性,著重于其雙選擇特性,結(jié)合各種幀結(jié)構(gòu)的特點(diǎn)詳細(xì)闡述了SC-FDE的基本原理；通過(guò)SC-FDE系統(tǒng)數(shù)學(xué)模型分析在快時(shí)變衰落環(huán)境中的干擾問(wèn)題,給出了干擾的數(shù)學(xué)表達(dá)式。其次,介紹了信道壓縮算法,給出了克服濾波器長(zhǎng)度受限及復(fù)雜度高的最大化縮短信噪比(MSSNR)算法的改進(jìn)方案。接著,通過(guò)在SC-FDE系統(tǒng)中應(yīng)用SIRF時(shí)的余留干擾表達(dá)式的推導(dǎo),得出了SIRF改進(jìn)算法在系統(tǒng)中應(yīng)用的設(shè)計(jì)方案,并給出了頻域均衡MMSE算法等效噪聲估計(jì)。最后,通過(guò)Matlab仿真結(jié)果對(duì)上述理論結(jié)果進(jìn)行驗(yàn)證,得出快時(shí)變衰落環(huán)境中CP不足SC-FDE系統(tǒng)結(jié)合最佳參數(shù)設(shè)計(jì)的SIRF的線性均衡的抗干擾性能。
[Abstract]:Mobile broadband wireless communication systems usually need to deal with the interference caused by time-frequency double selectivity in the channel with limited spectrum bandwidth in fast time-varying fading environment.Therefore, it is of great significance to study the interference suppression equalization algorithm in band-limited dual selective channels.Although multicarrier transmission, such as orthogonal frequency division multiplexing (OFDM) technology, has its special advantages in compensating dual selective channels and its research results are mature, the problems such as peak to average ratio and high phase noise sensitivity are not conducive to practical application.Compared with OFDM, SC-FDE (single Carrier Frequency Domain Equalization) has low peak-to-average ratio (PAPR) and similar anti-multipath performance. Therefore, SC-FDE has attracted much attention in the research of broadband wireless communication in recent 10 years.However, the characteristics of bit stream time domain modulation and demodulation make the research of anti-jamming in fast time-varying fading environment different from that of OFDM system.In view of this, the paper studies the interference suppression problem of SC-FDE system in fast time varying fading environment.In this paper, the algorithm of compressed impulse response filter (SIRF) is studied and designed. Under the condition of finite length cyclic prefix (CPP), the interference in SC-FDE system is suppressed to reduce the bit error rate (BER) and maintain the spectral efficiency of the system.The main work of this paper includes the improved algorithm of MSSNR-SIRF and the optimal performance parameter design of SIRF in fast time-varying fading channels.At the same time, the minimum mean square error criterion (MMSE) frequency domain equalizer under the optimal SIRF is improved by using the equivalent noise approximate estimation, which can restrain the noise interference to some extent.The main structure of this paper is divided into four parts.Firstly, this paper analyzes the characteristics of the channel in fast time-varying fading, focusing on its dual selection characteristics, and expatiates on the basic principle of SC-FDE in combination with the characteristics of various frame structures.Based on the mathematical model of SC-FDE system, the interference problem in fast time-varying fading environment is analyzed, and the mathematical expression of interference is given.Secondly, the channel compression algorithm is introduced, and an improved scheme is proposed to overcome the filter length limitation and the complexity of the maximum shortened SNR (MSSNR) algorithm.Then, through the derivation of residual interference expression when SIRF is applied in SC-FDE system, the design scheme of SIRF improved algorithm applied in the system is obtained, and the equivalent noise estimation of frequency domain equalization MMSE algorithm is given.Finally, the theoretical results are verified by Matlab simulation results, and the linear equalization performance of SIRF in fast time-varying fading environment with CP deficient SC-FDE system combined with optimal parameters is obtained.
【學(xué)位授予單位】：浙江工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN911.4
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本文編號(hào)：1743066