time is fading 中文意思是什麼

time is fading 解釋
時間漸逝
  • time : n 1 時，時間，時日，歲月。2 時候，時刻；期間；時節，季節；〈常pl 〉時期，年代，時代； 〈the time ...
  • is : be 的第三人稱，單數，現在時，陳述語氣。
  • fading : 淡變
  1. Therefore, during system design, cascade coding combining reed - solomon codes and convolutional codes is utilized ; in addition, time - direction and frequency - direction interleaves are added to alleviate channel fading

    因此在進行系統設計時，採用了rs碼與卷積碼的級聯編碼方案，並同時加入時間交織和頻率交織來對抗通道衰落。
  2. Shortwave channel is time varying transmission channel. it has dispersion in frequency and time domains. this characteristics hinds the data transmi - ssion at high speed and the correction of received data. in this dissertation i have analyzed the statistic characteristic of shortwa - ve channel, established the model of shortwave channel and simulated the rayl eigh fading distribution. the technology of spreading spetrum has been proved that it has the capability for anti - multipath and discerning multipath

    在短波通信中，由於通道的時間色散和頻率色散，引起多徑展寬和多徑衰落，前者限制了數據的傳輸速率，後者造成短波數據通信中出現突發錯誤，為了解決多徑效應對短波通信的影響，本文所做工作如下：首先詳細分析了短波通道的統計特性，建立其數學模型；其次分析了擴頻通信的特點，從理論上證明擴頻技術不僅具有抗多徑干擾能力，而且具有分離多徑的能力；介紹了傳統的rake分集合併技術的特點。
  3. Stbc ( space time block code ) is the main method to realize mimo diversity, and it is good at mitigating the influence of wireless multipath fading

    而stbc （ spacetimeblockcode ，空時分組碼）則是實現mimo分集的重要手段，長于對抗通道的多徑衰落。
  4. The theoretic formulas imply that mimo system can make use of multipath fading in full of scatter enviorment and its channel capcacity is in proportion to the transmt or receive antenna. 2. paper mainly explains the basic principle of bell laboratory layered space - time ( blast ) architecture

    2 .論文重點闡述了實現mimo系統中空間復用技術的貝爾實驗室空時分層（ blast ）結構的基本原理， blast結構作為實現mimo系統巨大容量的一種有效的手段，其核心是基於排序的串列干擾消除（ osic : orderingsic ）檢測演算法。
  5. Because the hybrid acquisition scheme ( combines parallel search with serial search ) based on the correlator provides the flexibility in the trade - off between the mean acquisition time and system complexity and is easy to implement, it ? focus on the scheme here. on the other hand, this paper analyzes the effect of multiple access inference ( mai ) on the code acquisition performance for the multipath fading channels

    基於相關器解擴的串-並混合方案由於有著可在平均捕獲時間和電路復雜程度（這是捕獲電路的兩個重要指標）這兩個技術指標間靈活折衷的優點和易於實現的特點，本文的重點就放在該方案中。
  6. The future wireless mobile communication systems are expected to provide ubiquitous, high - quality, and high - rate mobile multimedia transmission. however, hostile multipath fading radio conditions give rise to serious inter - symbol interference ( isi ) ; even worse, wireless channel are often time varying, which makes the system more vulnerable and more difficult to track the channel state. orthogonal frequency dvision multiplexing ( ofdm ), which is inherently resistant against isi, has invoked a popular research interest in recent years, and has been a promising candidate technology of the physical layer for future weideband high - date - rate wireless communications. notwithstanding, ofdm is much more vulnerable to errors of both time and frequency synchronization and to that of channel estimation, and how to obtain correct timing and channel estimation efficiently is highly critical to ofdm systems. the dissertation will focus on both of the aspects of ofdm systems mentioned above

    但是無線環境的多徑特性造成通信系統中嚴重的符號間干擾，同時無線通道的時變性使得通道特性跟蹤復雜。而正交頻分復用技術（ orthogonalfrequencydivisionmultiplexing ， ofdm ）正是一種解決符號間干擾的有效傳輸手段，因此ofdm技術作為未來寬帶高速率無線通信的物理層候選技術在當前引起了一股研究熱潮。但ofdm系統對定時同步誤差和通道估計誤差非常敏感，如何在ofdm系統中準確快速地實現符號同步和通道估計是至關重要的，本論文將重點針對這兩個問題進行討論。
  7. Abstract : by comparing the channel capacities hetwem orthogonal space - time block coding and multi - antenna array system over rayleigh fading channel, some capacity loss for orthogonal space - time block coding is obtained, which is a function of the code rate, the rank of channel matrix and the number of transmitter and receive antennas, although the system of orthogonal space - time block codes is simple and easy to implemented. if is also shown that there is no capacity loss only if both the code rate and the channel matrix rank are all one

    文摘:在研究瑞利衰落條件下正交空時分組編碼通道容量的基礎上，將其與多發送多接收天線系統的通道容量進行了比較.比較結果表明，正交空時分組碼雖編碼簡單，易於實現，但在通道容量方面存在較大的損失，損失的程度與編碼碼率、通道矩陣的秩及收發天線數等因素有關.進一步研究表明只有當編碼碼率和通道矩陣的秩都為1時，才沒有通道容量的損失
  8. Section 4 researches on pilot symbol aided space - time 2d rake receiver in rayleigh fading channel. two kinds of 2d - rake receivers are proposed, one is the interference zeros force 2d - rake receiver ( zf - 2drake ). simulation results reveal zf - 2drake has the better performance than the conventional 2d - rake receiver

    研究了rayleigh通道下2種導頻輔助的空時2d - rake接收機結構:干擾置零2d - rake接收機（ zf - 2drake ）和基於空時通道估計的時空級聯2d - rake接收機（ spce - 2drake ） ，推導了它們的誤碼率性能。
  9. Two approaches to improve the robustness of the detector, each based on a different theirs distortion mechanism. one is based on the modeling as fast fading distortion ( ffd ) whose optimum detector is the segmented replica correlator ( src ). the second approach is replica correlation integration ( rci ) for time spreading channel ( tsd )

    從頻率擴展通道（ fastfadingdistortion ， ffd ）和時間擴展通道（ timespreadingdistortion ， tsd ）的形成機理出發建立了目標回波的數學模型，指出ffd和tsd的最佳檢測器分別為分段副本相關器（ src ）和副本相關積分器（ rci ） 。
  10. 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。
  11. 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。
  12. 3 a novel recursive least - square ( rls ) blind space - time receiver algorithm based on the constrained condition, which can completely avoid the matrix inversion introduced into by constraints ( comparing with the normal rls ), is proposed for multi - path slow fading cdma channels. the computational complexity of this method is not only lower than that of the normal rls, but also lower than that of both lms and ls blind space - time receiver methods that are realized based on the rosen ' s gradient projection. and the speed of convergence of the presented rls blind space - time receiver algorithm is better than that of both lms and ls blind space - time receiver methods

    3 、針對多徑慢衰落通道下ds - cdma盲空時接收機中線性約束二次規劃問題提出一種新的遞歸最小二乘演算法，該演算法完全避免因約束而引進的矩陣求逆運算（相對于常規的遞歸最小二乘演算法） ，不但運算量比常規的要低，而且比基於rosen梯度投影實現的最小均方（ lms ）與最小二乘盲空時接收機演算法還低，且收斂速度比基於rosen梯度投影實現的最小均方（ lms ）與最小二乘盲空時多用戶檢測都好，將提出的新的遞歸最小二乘演算法與提出的數據選擇方案結合起來可以進一步降低其運算量，具有很大的實用價值，最後通過模擬實驗進一步分析了其性能。
  13. Combined with the data - selected schemes proposed, the computational complexity of this method can be lowered. the performance of the presented rls method is analyzed by simulations, and it is shown that this method is interesting for application. 4 time - selective channel signal model based on multipath - doppler diversity representation is given in multi - path fast fading channel, and rls space - time receiver algorithm based on time - varied constraint condition is presented and the computational complexity of this method is analyzed

    4 、針對多徑快衰落通道下的ds - cdma系統，給出了基於多徑-多譜勒觀點描述的1百安電弓卜科東兔j憶學協士學位論文時間選擇性通道的信號模型，提出了基於變約束條件下的遞歸最小二乘空時接收機演算法並分析演算法的運算量，最後通過模擬分析了所提出的方法的性能。
  14. Then the performance for sttc in multipath and time - dispersive fading channels is derived. in chapter 5, space - time block coding ( stbc ) is studied

    研究了空時格狀編碼在多路徑和時間色散的衰落通道中的性能，得到它的性能限。
  15. In chapter 4, space - time trellis coding ( sttc ) is studied. an exact pairwise error probability is derived for space - time codes operating over rayleigh fading channels

    在第四章中，研究了空時格狀編碼的問題，推出了誤碼概率的確切表達式。
  16. We propose the joint filterbank precoders and decision feedback equalizers structure at first, by which the dispersive channel is equivallent into parallel independent flat fading subchannels such that the diversity gain of the receiver is increased. then we adopt the discrete - time ( dt ) canonical model to convert the problem of blind signal processing of tv dispersive channels into processing the time - invariant multi - channels model blindly, and discuss the problem of blind equalization and identification of tv dispersive channels based on this new model

    第一種是採用濾波器組聯合均衡方法將色散通道等價為一組獨立的平坦衰落子通道，以提高接收機的分集增益；另外一種是提出採用離散正則模型將時變色散通道的盲信號處理轉化為時不變多通道模型的盲信號處理，並針對該模型對時變色散通道的盲均衡與盲辨識方法進行了詳細討論。
  17. A time - varying disperse channel is a channel that contain both frequency selective fading and time selective fading

    時變色散通道則是同時存在頻率和時間選擇性衰落的通道。
  18. At this time, the talented hunk na lan zheng de ken tong comes into the picture and easily steals the lonely heart of jing - jing. realizing that the love from jing - jing is fading away, rong bares his heart again but sadly that it is just too late

    菁暗中助榮，德見菁對榮餘情未了，妒火中燒，遂起殺機，卻錯手殺死鴻之子黃俊義李國麟
  19. The simulation results based on siso and mimo systems show that the proposed scheme could effectively eliminate the time - variant fading characteristics of wireless channel and under an acceptable demand of ber, the frequency efficiency is enhanced greatly and besides, dynamic encoding is implemented with low complexity and high efficiency

    通過在單天線和多天線系統中的模擬，表明該方案可以有效的克服無線通道的時變衰落特性，在滿足誤碼率性能要求的基礎上可以提高系統頻譜利用率，且實現復雜度低。
  20. Delivering quality video over wireless channels in real time is a challenging task. this isprimarily because of the throughput of a wireless channel may be reduced due to multipath fading, cochannel interference, and noise disturbance. therefore, there is a critical need forrobust transmission of video over wireless channels. recently, the emergence of mimo - ofdm has stimulated great interest in real time video communication, because this system can offer broadband for the multimedia data transmission over wireless channels

    因為傳統的視頻壓縮技術是針對單天線系統，只產生單一的比特流，這與多天線系統不相適應，為此，需要將視頻信號分解成相應的多個碼流。本文探討一種將能視頻信號分解成多個碼流的多描述編碼方法，以適應多天線系統的傳輸。
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