frequency selective fading 中文意思是什麼
frequency selective fading
解釋
頻率選擇性衰落（色散衰落）-
Single carrier frequency domain equalization for high data rate transmission systems over frequency selective fading channels
頻率選擇性通道下高速數據傳輸中的單載波頻域均衡技術 -
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 problems of carrier frequency offset estimation under the condition of the agwn channel, frequency flat - fading channel and frequency selective - fading channel are studied in detail respectively
本文仔細研究了在高斯白噪聲通道下、頻率平坦衰落通道下和頻率選擇性衰落通道下高精度估計信號載頻偏差的問題，並對相應演算法提出了一些改進辦法。 -
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。 -
Frequency selective fading
頻率選擇性衰落色散衰落 -
Because of the different time delay among multi - paths, the received signal undergoes frequency - selective fading
由於多徑干擾之間具有不同的時間延遲，接收信號將承受頻率選擇性衰落。 -
The tapped delay model of the multi - path frequency selective fading channels as well as the diversity receiver technique is introduced, and the principles of rake receiver are described. then various downlink channel estimation techniques, such as simple averaging, wmsa and fbprelms are analysed in detail
本文首先討論了移動通信通道的各種參數對通道估計的影響，介紹了頻率選擇性通道的抽頭延遲線模型和分集接收技術，在此基礎上闡述了rake接收機的原理。 -
Subsequently the channel was modeled for three types namely additive white gaussian noise, flat fading and frequency selective fading. lastly, the receiver was studied
接下來通道建模成三種不同的類型，即加性高斯白噪聲通道、平坦衰落通道和頻率選擇性衰落通道。 -
Based on the research of mimo detections under the flat fading channel, this paper focuses on the mimo detection under the frequency selective fading channel, chiefly aiming at the lll detection algorithm
在對平坦衰落通道下mimo檢測技術研究的基礎上，本文展開了對頻率選擇性通道下mimo檢測技術的研究。 -
In wireless digital transmissions, due to the delay dispersion of the transmitted symbols and the limitation of channel bandwidth, the channel may induce inter - symbol interference ( isi ), which results the frequency selective fading
在無線數字傳輸中，由於時延擴展和通道帶寬限制，引起碼間串擾，產生頻率選擇性衰落。 -
In recent years, there has been a lot of interest in applying orthogonal frequency division multiplexing ( ofdm ) in wireless systems because of its various advantages in lessening the severe effects of frequency selective fading
近年來，正交頻分復用（ ofdm ）作為一種具有高傳輸效率以及良好的抗頻率衰落性能，得到了廣泛的關注。 -
Also, new expression of ser of mqam in frequency selective fading channel with rake combining is obtained, and throughput performance adaptive mqam with rake receiver in multipath rayleigh fading channel is analyzed
本文還得到了mqam在頻率選擇性衰落通道中採用rake合併新的誤碼率表達式，並對採用rake接收的自適應mqam在多徑瑞利衰落通道中吞吐量性能進行分析。 -
Comparison study between the constant modulus decision feedback equalizer ( dfe ) and several others is made on combating the frequency selective fading of uwac, and their tracking performance to time varying is also investigated
?針對水聲通道的頻率選擇性衰落，對比研究了常數模判決反饋盲均衡演算法與其它幾種盲均衡演算法的性能。針對水聲通道的時變特性，研究了該演算法的跟蹤摘要性能。 -
However, to achieve this objective, various technical challenges must be overcome. for example, the deployment of broad - band wireless access systems would require a transmission technique which can mitigate the detrimental effects of frequency selective fading
為達到這一目的，有一些技術問題必須得到良好的解決，比方說在寬帶通信模式下由於延遲擴展造成的頻率選擇性擴展和由多普勒效應產生的通道時域衰落。 -
With the downlink simulation model constructed, performance of wideband cdma under different radio propagation environment and vehicular speed is simulated. based on system model of mc ds cdma under flat fading channel with relative shifts of spreading sequences within 1 chip and frequency selective fading channel with arbitrary relative chip shifts, performance of multicarrier cdma system with go sequences under different radio environment is investigated
基於多載波直接序列碼分多址在乎坦衰落通道中序列偏移小於1個碼片及在頻率選擇性衰落通道中偏移任意個碼片的系統模型，本文還分析了採用廣義正交序列的多載波碼分多址系統在不同無線傳播環境下的性能。 -
Finally, performance of adaptive modulation and coding in 11sdpa system is investigated. multi - code channel structure of physical layer, coded modulation schemes and adaptive transmission parameter selection are analyzed. simulation implementation of fading compensation in flat fading channel and maximum ratio combining ( mrc ) in frequency selective fading channel is investigated
最後，本文還研究了hsdpa中自適應調制與編碼性能，分析了物理層多碼通道結構、編碼調制方案、自適應傳輸參數選擇，並研究了平坦和頻率選擇性衰落通道中衰落補償和最大比合併（ mrc ）的模擬實現。 -
Frequency - selective fading due to multipath propagation is a big obstacle in wireless communication. in the condition, the intersymbol interference ( isi ) comes into being and communication system appears error received symbol
多徑傳輸效應引起的頻率選擇性衰落是無線通信的一大障礙，使接收信號產生碼間干擾（ isi ） ，導致通信系統出現誤碼。 -
This article proposes the adaptive algorithm based on equal snr signal noise ratio, and applies it in adaptive ofdm system. in frequency selective fading channel, compared with the traditional ofdm system based on equal power allocation, the system outperforms in ber bit error ratio performance
提出了一種基於最小平均誤碼率的自適應預處理演算法，並將該演算法應用於自適應ofdm系統，在頻率選擇性衰落通道條件下，與等功率分配的ofdm系統相比，誤比特性能有了很大程度的提高。 -
Because using ofdm, a frequency - selective fading channel can be transformed into multiple frequency - flat fading sub - channels, in the coding process, spatial diversity ( due to multiple antennas ) is integrated with frequency diversity ( due to delay spread ), therefore, the proposed code can provide higher diversity gain than space - time code alone
該編碼利用正交頻分復用把頻率選擇性衰落通道變換成平衰落通道的特性，同時引入了基於多天線的空間分集和基於時延擴展的頻率分集，比空時編碼具有更高的分集增益。 -
The theoretical results are evaluated by simulation. if the coherent bandwidth of channel doesn ’ t exceed the occupied bandwidth of two chips, with the increase of delay spread of the channel, mc - ss - cldd exhibits a better performance to make the system resistant to frequency - selective fading
研究結果表明，多載波擴頻碼片級差分檢測在單用戶和多用戶情況下，均適合於時變頻率選擇性衰落通道，並具有抵抗頻率選擇性衰落的能力。
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