time varying channel 中文意思是什麼

time varying channel 解釋
時變通道
  • 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 ...
  • varying : 變化的
  • channel : n 1 水路，水道，渠，溝；海峽；河床，河底。2 （柱等的）槽，凹縫；【機械工程】槽鐵，凹形鐵。3 〈比...
  1. A channel estimator for multi - carrier system in fast time - varying fading channels

    一種快時變通道下多載波傳輸系統的通道估計方法
  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. The super - exponential iteration ( sei ) blind equalization algorithm has the advantage of good tracking capability of the time varying channel

    超指數盲均衡演算法的迭代演算法收斂速度快，且便於跟蹤時變通道。
  4. This method provides unequal protection for spiht bet stream with different importance, and adaptively adjusts the source and channel coding rates according to the time - varying characteristic of the channel, thus yields good performance and high reliability without adding extra bandwidth. simulations in rayleigh channel show that the scheme can obviously improve the image quality compared to eep and uep scheme, especially when the channel is in bad condition

    本方法通過對spiht編碼碼流重要性的不同而進行不同程度的保護，並利用通道的時變特性自適應地調整信源和通道編碼速率，從而在不增加額外帶寬的前提下有效地提高了系統的性能和可靠性，經過計算機模擬模擬，得出了在瑞利通道中，傳輸條件惡劣的情況下，本方法比eep和uep能更好的提高重建圖像的質量。
  5. 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。
  6. 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。
  7. We can reduce the isi and noise by elaborately designing transmitting filter and the receiving filter when the channel is known and unaltered. however, the factual channel is time - varying and not known entirely. so the isi is always existent

    在通道特性已知且恆定的情況下，通過精心設計發送和接收濾波器就可以消除碼間干擾和使噪聲的影響最小，但實際通道既不可能完全知道，也不可能恆定不變，系統碼間干擾總是存在。
  8. Statistics and simulations of wssus time - varying simulations multipath channel

    時變多徑通道的統計特性與模擬
  9. Precise simulation model design of ofdm systems working under time - varying dispersive channel

    系統在時變色散通道中的精確建模與模擬
  10. 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。
  11. According to wireless and mobile communication system ' s background, this thesis study on estimation of time - varying dispersive channel from four respects : ( 1 ) aid of pilots, ( 2 ) cyclic prefix ( cp ), ( 3 ) blind method, and ( 4 ) ofdm system with multiple transmitting antenna, in which the typical ways is decision - feedback algorithm and self - adaptive block algorithm

    本文以無線和移動通信系統為背景，從四個方面對時變色散通道下的ofdm系統的通道估計和均衡問題進行了研究。第一是基於導頻符號的通道估計方法，第二是基於循環前綴的通道估計方法，第三是通道的盲估計方法，第四是基於多天線ofdm系統的通道估計和均衡方法的研究。
  12. A signal processing method comprises receiving a first signal for wireless communication, obtaining an approximate of a non - channel function in the first signal, separating the approximate of the non - channel function from the first signal to obtain a second signal that includes a time - varying channel function, and processing the second signal to obtain a user signal

    本發明提供一個信號處理方法，包括接收第一個無線信號；估計第一個信號中的脈沖成形失真；從第一個信號中分離出該脈沖成形失真以獲得第二個信號；以及處理第二個信號以獲得一個用戶信號。
  13. In this paper, the fundament, the system architecture and the application of orthogonal frequency division multiplexing ( ofdm ) were discussed, and the mathematic model of time - varying multi - path based on the discussion of mobile fading channel characteristic were analysed, and the channel model were discussed by computer simulation

    本文首先簡要介紹了正交頻分復用（ ofdm ）的基本原理、系統組成以及ofdm的實際應用。在分析移動通道衰落特性的基礎上，分析了多徑時變通道的數學模型；並用計算機模擬的方法對通道模型進行了討論。
  14. The propagation characteristics of underwater acoustic channels and their influences on long - range information transmission are studied thoroughly. based on the sonar equation, the optimal frequency band is abtained. from the calculation about transmission loss, the source level is forecasted. based on the random time varying channel theory, the fading characteristics of long - range underwater acoustic channels are analyzed

    系統、深入地研究了水聲通道特性及其對水聲遠程信息傳輸系統的影響；從聲納方程出發，確定了系統的最佳工作頻段；在聲傳播損失計算的基礎上，給出了聲源級的預報；基於時變通道理論，描述了遠程水聲通道的衰落特性。
  15. But the traditional adaptive equalizers need periodically retrained, because the underwater acoustic channel is a stochastic time - varying channel. although the traditional adaptive equalizer increase the reliability of the propagation, the rate of it is decreased. so they are not very applicable in the field of the propagation of high rate signals through an underwater acoustic channel

    但是由於水聲通道的隨機時變性，傳統的均衡技術需要周期性的發送收端已知的訓練碼來跟蹤通道的變化，這樣做雖然提高了數據傳輸的可靠性，但是系統的重復訓練大大的降低了通信效率，在水聲通道高速率數據傳輸中並不適用。
  16. The defect of thes powe control and allocation method is without consideraon of the induence of all of the other users on the desired user and the influence of time - varying channel, so it can not maximize the capacity, and deduces the frequency waste

    這種功率分配與控制方法的缺點是沒有考慮到系統內其他用戶對期望用戶的影響以及通道時變特性的影響，不能最大化系統的容量，造成了頻譜資源的浪費。
  17. Rtce is based on forecasting the inherent vulnerabilities to propagation of hf time - varying channel, including multipath delay, doppler spread, selective fading, interference, so this paper also introduces characteristics of hf channel in the beginning. familiar rtce systems all adopt envelope method that bello brought forward

    實時選頻技術是基於對短波電離層時變通道固有的不利於電波傳播的各種因素，包括通道的多徑展寬、多普勒展寬、選擇性衰落、噪聲干擾等的預測的基礎上實現的，所以在開篇對短波通道的特點進行了詳細的介紹。
  18. And key technologies of mc - cdma, channel estimations and diversity combinations, are mainly studied for the application of mc - cdma. the channel estimation based on pilot carriers is analyzed, and an improved method with wiener filtering is presented. simulations of the method are carried in time - varying multi - path channel

    本文分析了基於導頻的通道估計演算法，提出了採用維納濾波平滑的改進估計演算法，並在多徑時變通道下進行了計算機模擬，對系統各參數分別對通道估計誤差和誤碼率性能的影響做了詳細分析和比較，從而證明了演算法和改進的有效性。
  19. A polling - based adaptive beamforming multiple access ( pb - abfma ) protocol is proposed. in pb - abfma, the simple and effective mechanism is used to guarantee the smart antennas to adapt the time - varying channel. the cap schedules packet transmissions based on the polling mechanism and dynamic tdma

    該協議中採用簡單、有效的機制保證智能天線快速、準確地適應時變通道，以動態tdma方式為各節點安排發送時隙，採用微時隙為處于空閑狀態的用戶保持連接以降低接入時延，該協議可工作于異步網路中，具有很強的實用性。
  20. Radio resource allocation and scheduling is one of key functions to provide qos guarantees in wireless networks. current research focuses on design of efficient algorithms taking into account the special characteristics of the wireless environment such as time - varying channel capacity and location - dependent errors. these algorithms shall maximize the utilization of the wireless channels and guarantee qos for the users, while providing certain fairness between users

    其中，無線資源的分配與調度是提供qos保證的關鍵，當前的研究集中在針對無線通道容量的時變和位置依賴特性，設計演算法來有效利用寶貴的無線資源，支持用戶的qos要求，同時滿足一定的公平性。
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