衰落通道 的英文怎麼說
中文拼音 [shuāilàtōngdào]
衰落通道
英文
fading channel- 衰 : 衰動詞(衰弱) decline; wane
- 落 : 落名詞[方言] (北方對蓮花落的俗稱) a kind of folk song
- 通 : 通量詞(用於動作)
- 道 : Ⅰ名詞(道路) road; way; route; path 2 (水流通過的途徑) channel; course 3 (方向; 方法; 道理) ...
- 衰落 : decline; be on the wane; go downhill; fading; decay; decaying; lapse; erode
- 通道 : thoroughfare; passageway; pass; enterclose; gallery; drong; tunnel; avenue; alure; way; row; key ...
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And then facing the problem of the channel estimation of the adaptive modulation system, we conclude out the channel estimation algorithms on maximum likelihood ( ml ) estimation and maximum a posteriori ( map ) estimation under the condition of flat fading channel and selective fading channel in detail. to meet flat fading channel, we simulate the relationship of the ratio between the error covariance in map estimation and ml estimation and pilot symbol message length. the conclusion can be drawn from these results
接著,對自適應調制系統中的通道估計問題難點,詳細推導了平衰落通道條件下和選擇性衰落通道條件下最大似然( ml )估計和最大后驗概率( map )估計演算法,針對平衰落通道,我們模擬了map估計和ml估計的方差與導頻符號長度的關系,模擬結果表明,錯誤方差受多譜勒頻率的變化影響最大,並且對實際的自適應調制系統,導頻符號長度的取值超過20個符號長度時, map通道估計明顯優于ml通道估計。In rayleigh channel, the capacity is also improved
在瑞利衰落通道上,性能亦有改善。Then this paper makes some overview and simulation on the application of three precoding algorithms under the flat fading channel, which are linear preequalization, tomlinson - harashima precoding ( thp ) and lattice reduction - aided ( lll ) vector precoding
本文對三種常見的預編碼演算法在平坦衰落通道下的應用進行了綜述和模擬研究,包括迫零線性預均衡、 thp預編碼和格約簡輔助矢量預編碼等演算法。Turbo codes represent the new code structures, which consist of pccc ( parallel serially convolutional code ) and sccc ( serially concatenated convolutional code ). in this paper, the background of turbo codes are firstly introduced, which includes the base principle of error correction code 、 block code and convolutional code ; the principle of turbo code and the iterative decoding is secondly expanded ; the key decoding algorithm : a revised map algorithm and iterative decoding theory are detailed ; then, a new turbo code structure : hccc ( hybrid concatenated convolutional code ) is presented, and the capacity of this code method is analyzed, the average capacity upper bound is derived ; at last, this code is simulated on awgn ( additive white gaussian noise ) channel and rayleigh fading channel
本文首先介紹了turbo碼的背景知識,包括差錯控制的基本原理、分組碼和卷積碼;然後闡述了turbo碼的基本原理,包括turbo編譯碼器結構及迭代譯碼原理;較為詳細地描述了關鍵的譯碼演算法: ?種改進的最大后驗概率( map )譯碼演算法及迭代譯碼演算法;提出了一種新的turbo碼結構:混合turbo碼(混合級聯卷積碼) ;並用編碼性能聯合界分析方法對混合turbo碼進行了性能分析,得出了其平均性能上界;並在高斯白噪聲通道和瑞利衰落通道上分別作了一些應用研究及計算機模擬實驗。The basic idea of this method is to produce particles from the posterior densities, and these weighted samples provide approximations to the densities. in this dissertation, sequential monte carlo method and its applications in communication are investigated. firstly, its basic idea, method and improved method are introduced, then induce the bound of particles, which determines the performance of the system, and the more particles are chosen, the higher computation is done, finally, a new detector based on new importance function is proposed, which deals with the joint channel estimation and detection in flat fading channels
首先介紹了它的基本思想、基本方法、及當前研究現狀;在此基礎上推導出樣本數選擇的界,樣本數的選擇決定了系統的性能,但是若選的太多,計算復雜度也會隨之增大,因而給出這個界是十分有意義的;最後提出了一種基於新的重要函數的檢測器用來解決平坦衰落通道下的聯合通道估計和檢測問題,並通過模擬證明了我們提出的新檢測器的有效性。In this thesis, first, we present the theory of sess system, the generation of the sess spreading code and its characteristics and the acquisition theory of conventional spread spectrum communication system. an efficient acquisition scheme based on periodically transmitting the synchronization head, which is composed of binary chaotic codes, using the matched filter and automatic decision threshold - level control based on a so - called constant false alarm criterion for sess system is present. the acquisition model of sess system is built and simulated in the awgn channel, the raleigh fading channel and imulti - address interfere condition
本文首先概述了自編碼擴頻通信的原理、自編碼擴頻序列的產生方法及其特性和擴頻通信系統編碼同步的理論,然後針對自編碼擴頻通信系統提出了擴頻序列捕獲方案:周期性地加入混沌序列同步碼,並採用恆虛警率匹配濾波器捕獲法;在加性白高斯噪聲通道、瑞利衰落通道和多址干擾情況下進行了模擬,分析了各種捕獲性能:在選擇性能最優的混沌序列、適當的序列長度、虛警概率及門限值的情況下,可以獲得較短的捕獲時間和較大的捕獲概率。Diversity receiving technique for synchronous time spreading signal in time - varying fading channels
時變衰落通道中同步時間擴展信號的分集接收技術Under rayleigh fading channel, we also simulated and compared ber in siso 、 simo and mimo systems. secondly, based on careful study the ber and the channel capacity under white noise channel under mpsk modulation when the channel is rayleigh fading, we duduced the expressions of stbc ’ s ber and channel capacity under rice and nakagami fading. and also analysed the performances through numerical simulation using matlab to testify the exactitude of the dudeced expressions. finally, there exists an error floor of stbc through studying on its performance on time - selectiv fading channel. we analysed the reason and proposed two new decode combination scheme to eliminated the error floor and the performance of stbc on time - selective fading channel is improved. and also compared the two scheme ’ s complication and snr gain
這些結果大部分是閉式結果,能比較準確地衡量空時塊碼的性能,並對不同衰落的性能做了相互比較,其結果對空時塊碼的實際應用具有一定的指導意義。實際的通道是時變的,分析了空時塊碼在時間選擇性衰落通道中產生誤差地板效應的主要原因是存在碼間干擾( isi ) ,在此基礎上提出了兩種能消除誤差地板效應的譯碼合併方案,並對這兩種方案的復雜度和信噪比增益進行了比較。The conclusion is identified by computer simulation. the paper studies a noncoherent demodulation based on differential encoding in mc - cdma system and makes computer simulation of ber performance compared with that of coherent demodulation based on perfect channel estimation
研究分析了一種使用差分編碼的非相干接收mc - cdma系統,對頻率選擇性瑞利衰落通道條件下的誤碼率性能進行了計算機模擬,並且和基於理想通道估計的相干解調方案進行了比較。Adaptive coded modulation for rayleigh fading channels
瑞利衰落通道下的自適應編碼調制技術Performance analysis of variable - rate packet cdma system
瑞利衰落通道下差分跳頻通信系統性能分析The paper proposes a feedback pre - equalization ( f - pe ) method based on channel estimation in a frequency - selective rayleigh fading channel
在頻率選擇性瑞利衰落通道條件下,提出一種基於通道估計的反饋?預補償均衡檢測演算法。Then, we discuss the model of a 256 sub - carriers mc - cdma system and analyze ber performance in a frequency - selective rayleigh fading channel
討論了一個256載波的mc - cdma系統的數學模型,分析了在頻率選擇性瑞利衰落通道中的誤碼率性能。3. studying still image transmission systems without channel coding or with turbo codes over both awgn and rayleigh fading channels by matlab simulation. simulation results show that turbo codes not only advance the dependability of communication systems, but also reduce channel signal - to - noise ratio ( snr )
將turbo碼應用於靜止圖像傳輸系統,信源編碼採用矢量量化編碼,分別在awgn通道和rayleigh衰落通道下,對不採用通道編碼和採用turbo碼作為通道編碼的各種情況進行模擬。Appropriate data compression methods are needed to assure the random nature of the information source and to enlarge its entropy. in this thesis, first, we present the theory of sess system, then the acquisition method of sess system is discussed in detail, finally, a acquisition model of sess system is built and simulated in the awgn channel, in the raleigh fading channel and in multi - address interfere condition. the simulation results show the acquisition method of sess system can be just as reliable as the conventional dsss systems
本文首先對自編碼擴頻通信的基本原理,自編碼擴頻序列的產生方法及其產生的序列的特性進行了概述,然後詳細討論了直擴通信系統中的擴頻碼的捕獲跟蹤問題,根據自編碼擴頻通信的特點,設計了其捕獲跟蹤方案,並在加性高斯白噪聲通道、瑞利衰落通道和多址干擾情況下進行了模擬。Blind equalization is an effective way to suppress the inter - symbol interference ( isi ), which is caused by multipath fading communication channels
摘要在數字通信中,盲均衡是克服多徑衰落通道導致的碼間干擾的一種有效方法。In this dissertation, multiuser detection and space - time processing are combined to suppress multiple access interferences and inter - symbol interferences ( isi ) jointly in multipah fading channels with large delay spread
本文組合多用戶檢測和空時處理技術,在大時延擴展的多徑衰落通道條件下,研究多址干擾和符號間串擾的聯合抑制。A new approach to equalization of linear single - input single - output time - selective fading channel
時間選擇性衰落通道迫零均衡新方法The following algorithms have been proposed and tested in the thesis : 1 frequency selective fading : combine the isomorphism between the input space and the output space and propose a new approach to blind equalization of the channel. compared with conventional methods, the new approach offers lower computational complexity, better performance, and more robust against the over - determination of the system order ; 2 time selective fading : a new approach to the equalization of time selective channel based on the zero - forced equalizer is proposed which is more simple in its structure of algorithm ; 3 time - varying channel : using the instantaneous mean value changes of the output signal to extract the information of channel variations and model it using ar model, kalman filter is then employed to track channel variations, it bears faster ability in tracking the variation of tv channels ; based on the isomorphism between the inputs and the outputs and some of the approaches using in mimo system, a new algorithm of equalization of simo time - varying channel is proposed, which also share the merits of being robust against the over - determination of the system order ; model the time - varying channel using the multi - resolution decomposition wavelets, and then a blind identification method based " on the model is proposed ; at last, a new model for equalization and identification of mimo system is proposed
主要工作在以下幾個方面: 1 、針對頻率選擇性衰落通道:結合輸入輸出空間同構關系提出一種新的頻率選擇性通道均衡方法,與傳統方法相比,該方法計算量更小,收斂速度更快,性能更優,且對系統階次的過確定表現穩健,具有實際均衡應用價值; 2 、針對時間選擇性衰落通道:提出一種基於迫零均衡的時間選擇性通道均衡方法,演算法結構簡單; 3 、針對時變色散通道:利用瞬態均值曲線提取通道時變信息,對之ar建模,利用卡爾曼濾波器跟蹤時變通道抽頭變化,可以快速跟蹤通道變化;基於輸入輸出空間之間的同構關系以及多輸入多輸出系統的處理方法,提出了新的單輸入多輸出色散時變通道均衡與識別演算法,同樣具有對通道階次過確定保持穩健的優點;結合小波多解析度分析提出一種基於小波模型的通道盲識別演算法;研究時變的多輸入多輸出系統的盲均衡與盲反卷積問題,給出一種時變系統處理模型。The simulation shows that under the fast fading channel circumstance, the wrls - svm channel estimation can acquire the high error performance
模擬結果表明,在快衰落通道條件下,小波遞歸最小二乘支持向量機導頻通道估計方法可以獲得較好誤碼性能。分享友人