selective channel 中文意思是什麼
selective channel
解釋
選擇通道-
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。 -
The instrument is integrated with a multi - channel high precision open circuit potential measurement system for the ion selective electrode and a potentiostat used in voltammetry, an analog lock - in amplifier is also presented to measure the response of light addressable potential sensor
對于不同的測量技術，儀器中集成了用於測量電極的多通道高精度開路電壓測量系統和用於溶出伏安法測量的多路電化學測量系統，以及用於測量光尋址電位傳感器的鎖相放大器。 -
In this thesis, for the merits of high frequency spectrum utility factor and high - speed data communication, the ofdm is introduced into the underwater acoustic communication. combined with fec to combat the frequency - selective fades and isi in the underwater acoustic channel, high speed data transmission is realized by employing ofdm technology
本研究嘗試將ofdm技術引入水聲通信領域，利用該技術頻譜利用率高，多載波并行傳送的特點，結合通道編碼，以克服水聲通道多徑干擾引起的頻率選擇性衰落和碼間干擾，獲得高速率數據傳輸。 -
Space - time codes can be divided into tree mainly parts : bell layered space - time architecture ( blast ), space - time trellis codes ( sttc ) and space - time block codes ( stbc ). in this paper, we mainly compare the performance of blast and stbc in many aspects, such as design criterion, transmission rate, diversity gain, diversity combining, bit error rate and channel capacity etc. in this paper, we first respectively analysed the instantaneous received symbol energy - to - noise ratio of v _ blast in the diversity combining methods of maximal ratio combining ( mrc ), equal gain combing ( egc ) and selective combing ( sc )
Mimo技術核心是空時編碼（ stc ） 。空時編碼主要分為三種:分層空時碼（ blast ） 、空時格碼（ sttc ）和空時塊碼（ stbc ） 。本文主要對分層空時碼和空時塊碼這兩種編碼方式在設計準則、傳輸速率、分集增益、接收合併、比特差錯率和通道容量等方面進行了較為詳盡的研究。 -
Causes small transmission delay, but computation is complex. the other is called dsova, which does not need to know csi, with low - computation complexity and small transmission delay, and is more suitable in the case when side information is unknown. these two algorithms effectively combine the ofdm technology and the sova algorithm in rayleigh channel, resulting in an efficient sova decoding under frequency - selective channel
另一種是不含通道估計的差分sova演算法（簡稱dsova ） ，該演算法不必知道csi ，計算復雜度低，傳輸時延小，適用於邊沿信息（ sideinformation ， si ）未知的情況，這兩種演算法將ofdm技術和rayleigh通道下的sova譯碼演算法有機的結合起來，很好地實現了頻率選擇通道下的sova譯碼。 -
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 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。 -
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。 -
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。 -
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。 -
Finally, the application of mud in the frequency - flat slowly fading multi - path channel is introduced, and to enhance the system efficiency the joint use of the rake receiver and mud is applied in the frequency - selective slowly fading multi - path channel
最後，在討論了平坦慢衰落通道的基礎上，將rake分集技術和多用戶檢測技術相結合應用於多徑的頻率選擇性慢衰落通道，以達到改良系統的性能的目的。 -
Since the underwater channel is nonstationary and the fades is frequency - selective, it is hard to use the real - time channel equalization technology
傳統的串列通信為了保證數據的可靠傳輸，必須實時地進行自適應的通道均衡。 -
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。 -
Then several kinds of selective k + channel blockers were applied to further clarify the specific type of k + channels involved in apoptosis. both bkca channel blockers, ibtx and chtx ( at the concentration of 100 nm ), significantly reduced neuronal death and number of positive tunel - staining cells and inhibited caspase - 3 activation
通道阻斷劑100nmibtx或100nmchtx均有顯著的神經元保護作用，可減少tunel陽性細胞比例及抑制caspase上激活；然而， a型鉀通道阻斷劑4apo0qm ）或skc 。 -
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。 -
It combines the advantages of ofdm and cdma. it can convert the frequency selective channel propagation of the broadband to flat channel of the subcarrier
它結合了ofdm和cdma技術的優點，能夠把寬帶頻率選擇性衰落轉化為每子載波的平坦通道。 -
So far, there is not much research on the signal detection of da - mimo system, and the general frequency selective channel is not taken into consideration. in chapter 3 of this dissertation, the coherent signal detection algorithms for da - mimo system under both flat fading and frequency selective fading channels are derived. and the analysis of the factors which affect the performance of the detection algorithms is also illustrated through computer simulations
針對分佈mimo信號檢測目前研究較少，並且沒有考慮一般意義下的頻率選擇性通道的情況，本文在第三章分別推導了基於平坦衰落和頻率選擇性衰落通道環境的分佈mimo信號相干檢測演算法，並通過計算機模擬，對影響演算法檢測性能的因素進行了分析討論。
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