本文選題：單載波頻域均衡 + 碼間干擾　； 參考：《重慶大學(xué)》2014年碩士論文

【摘要】：單載波頻域均衡（SC-FDE）技術(shù)創(chuàng)造性地將單載波技術(shù)和頻域均衡技術(shù)結(jié)合起來，不僅可以有效地克服由多徑效應(yīng)帶來的碼間干擾（ISI），實(shí)現(xiàn)可靠的高速率通信，而且能夠顯著減小單載波時(shí)域均衡（SC-TDE）技術(shù)龐大的運(yùn)算量和正交頻分復(fù)用技術(shù)（OFDM）過高的峰均比。單載波頻域均衡以其技術(shù)上的優(yōu)勢(shì)，逐漸成為近年來的研究熱點(diǎn)，，同時(shí)也被納入到IEEE802.16（WiMAX）標(biāo)準(zhǔn)中作為下一代寬帶無線通信系統(tǒng)物理層的重要解決方案。 論文重點(diǎn)研究SC-FDE系統(tǒng)中的頻域均衡技術(shù)，并圍繞現(xiàn)有均衡算法中存在問題展開，探討如何在信道估計(jì)精度與計(jì)算復(fù)雜度兩個(gè)方面取得最佳平衡，從而提高SC-FDE系統(tǒng)性能。論文的主要工作有： ①論文從介紹SC-FDE基本原理入手，歸納現(xiàn)有頻域均衡的關(guān)鍵技術(shù)，包括均衡算法，信道估計(jì)算法和插值算法，并對(duì)其比較分析，總結(jié)各種算法在估計(jì)精度和運(yùn)算復(fù)雜度上的優(yōu)缺點(diǎn)，為論文后續(xù)的研究工作提供切入點(diǎn)； ②針對(duì)SC-FDE系統(tǒng)傳統(tǒng)功率恒定的幀結(jié)構(gòu)進(jìn)行功率調(diào)整，提出在時(shí)域?qū)Y(jié)構(gòu)中UW塊和FFT塊功率進(jìn)行再分配的概念，通過對(duì)符號(hào)能量分配因子的仿真設(shè)計(jì)，解決功率的最優(yōu)化分配問題，仿真結(jié)果表明，在數(shù)據(jù)幀總能量不變的情況下，功率優(yōu)化后系統(tǒng)與優(yōu)化前相比提高了誤碼性能； ③針對(duì)傳統(tǒng)LS算法信道估計(jì)精度不高和IFFT/FFT濾波算法實(shí)現(xiàn)難度太大的問題，論文根據(jù)后者消除估計(jì)信道中時(shí)域噪聲的思想，提出一種改進(jìn)的自適應(yīng)濾波LS算法。該方法在傳統(tǒng)LS算法變換域插值的時(shí)域增加自適應(yīng)濾波器，并根據(jù)信道能量和噪聲方差設(shè)計(jì)出能夠跟蹤信道變化的濾波器系數(shù)，從而避免虛檢和漏檢現(xiàn)象，通過在多徑信道中仿真結(jié)果的分析，自適應(yīng)濾波LS算法在信噪比適中的區(qū)間能夠得到比上述兩種算法更高的信道估計(jì)精度； ④為了解決MMSE均衡中對(duì)信道噪聲方差的需要，論文結(jié)合SC-FDE系統(tǒng)幀結(jié)構(gòu)的特點(diǎn)，提出一種基于后向反饋結(jié)構(gòu)的信噪比估計(jì)MMSE均衡算法，該方法在經(jīng)過了ZF均衡的FFT塊中，采用ML算法對(duì)其冗余的UW序列進(jìn)行噪聲方差的估計(jì)，并將估計(jì)值作為參數(shù)對(duì)FFT塊再次進(jìn)行MMSE均衡。仿真結(jié)果表明，該算法在不增加額外開銷的情況下，能夠達(dá)到近似傳統(tǒng)MMSE算法的性能。
[Abstract]:Single carrier frequency domain equalization (SC-FDE) technology combines single-carrier technology with frequency-domain equalization technology creatively. It can not only effectively overcome the inter-symbol interference (ISI) caused by multipath effect, but also realize reliable high-speed communication. Moreover, it can significantly reduce the huge computational complexity of single carrier time domain equalization (SC-TDE) technology and the high peak to average ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) technology. Single carrier frequency domain equalization has become a research hotspot in recent years due to its technical advantages, and has also been incorporated into the IEEE 802.16 WiMAX standard as an important solution to the physical layer of the next generation broadband wireless communication system. This paper focuses on the frequency-domain equalization technology in SC-FDE systems and discusses how to achieve the optimal balance between channel estimation accuracy and computational complexity around the existing equalization algorithms so as to improve the performance of SC-FDE systems. The main work of the thesis is as follows: 1. Starting with the introduction of the basic principle of SC-FDE, this paper summarizes the key technologies of frequency domain equalization, including equalization algorithm, channel estimation algorithm and interpolation algorithm, and compares and analyzes them. The advantages and disadvantages of various algorithms in estimation accuracy and computational complexity are summarized to provide a starting point for further research work in this paper. (2) aiming at the traditional frame structure of SC-FDE system with constant power, the concept of redistributing UW block and FFT block power in time domain is proposed. The simulation design of symbol energy allocation factor is carried out. In order to solve the problem of optimal power allocation, the simulation results show that the error performance of the optimized system is improved compared with that before the optimization when the total energy of the data frame is invariant. 3 in view of the problem that the channel estimation accuracy of the traditional LS algorithm is not high and the IFFT/FFT filtering algorithm is too difficult to realize, an improved adaptive filtering LS algorithm is proposed according to the idea of eliminating the time-domain noise in the channel estimation by the latter. This method adds adaptive filter in time domain interpolation of traditional LS algorithm transform domain, and designs filter coefficients which can track channel change according to channel energy and noise variance, so as to avoid false detection and miss detection. Through the analysis of the simulation results in multipath channel, the adaptive filtering LS algorithm can obtain higher channel estimation accuracy than the above two algorithms in the range of moderate SNR. 4 in order to solve the need of channel noise variance in MMSE equalization, this paper presents a MMSE equalization algorithm based on backward feedback structure, which is based on the characteristics of frame structure of SC-FDE system. This method is used in the FFT block of ZF equalization. ML algorithm is used to estimate the noise variance of its redundant UW sequence, and the estimated value is used as a parameter to MMSE equalize the FFT block again. Simulation results show that the performance of the proposed algorithm is similar to that of the traditional MMSE algorithm without additional overhead.
【學(xué)位授予單位】：重慶大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN92

【參考文獻(xiàn)】

相關(guān)期刊論文 前3條

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本文編號(hào)：1929757