衰落效應 的英文怎麼說

中文拼音 [shuāilàxiàoyīng]
衰落效應 英文
fading effect
  • 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
  • 效 : Ⅰ名詞（效果; 功用） effect; efficiency; result Ⅱ動詞1 （仿效） imitate; follow the example of 2 ...
  • 應 : 應動詞1 （回答） answer; respond to; echo 2 （滿足要求） comply with; grant 3 （順應; 適應） suit...
  • 衰落 : decline; be on the wane; go downhill; fading; decay; decaying; lapse; erode
  • 效應 : [物理學] effect; action; influence
  1. 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。
  2. This thesis analyzed the error performance of mfsk and mpsk modulator in hf with optimal receiver, studied the shortcoming and strongpoint of several typical short - wave data transmission systems and their performance over fading and intersymbol interference channels. the theory and key technical of adaptive modem is discussed. in the last, an efficient modulation scheme - block coded modulation is introduced into hf radio systems to improve the efficiency of hf data transmission, this paper also proposes a hf data transmission system scheme composed of a block coded modulator and a decision feedback type adaptive equalizer

    本文在對短波數傳兩種常見調制方式fsk及psk最佳解調性能分析的基礎上，討論了幾種採用典型調制技術的短波數傳系統（如時頻調制、多進制頻移鍵控慢跳頻、 chess系統）原理、優缺點以及抗衰落和抗符號間干擾的性能；分析了自適應串列數傳系統抗短波通道衰落和多徑干擾的原理、關鍵技術；在本文的最後引入一種有望解決短波數傳系統低效率狀況的調制方式bcm -分組編碼調制，給出了一個採用bcm技術與自適應均衡技術相結合的短波數傳系統方案，並通過計算機模擬進行了初部驗證。
  3. 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。
  4. Aiming at the lower performance and floor effect of the traditional orthogonal frequency division multiplexing channel estimation, the ofdm channel estimation algorithm based on wavelet recursive least square support vector machine ( wrls - svm ) is proposed

    摘要針對傳統多徑衰落下的ofdm導頻通道估計性能低下，地板效應的缺陷，提出了基於導頻的小波遞歸最小二乘支持向量機（ wrls - svm ）時變通道頻率估計演算法。
  5. Contributions in this paper mainly sh ow four points : 1 the structure characteristic of the received ds - cdma signal is analyzed in the presence of multi - path slow fading effect case for wireless mobile communication. according to this characteristic, four data - selected schemes based on chip - matched filter are presented from the perspective of energy and structure of signal. and the impact of these schemes on multiple - access interference ( mai ) and inter - symbol interference ( isi ) is analyzed

    本文的主要貢獻在於四個方面： 1 、針對無線移動通信系統中廣泛存在多徑慢衰落效應的情況，分析了ds - cdma系統中接收信號本身的結構特徵，根據這個特徵，在匹配濾波的基礎上，從能量與信號結構的角度提出了四種不同的數據採用方案，並分析了不同數據方案對多址干擾與碼間干擾的影響。
  6. This paper proposes a multiple description mesh - based motion coding method, which generates two descriptionsfor mesh - based motion by subsampling the nodes of a right - angledtriangular mesh and dividing them into two groups. motion vectorsassociated with the mesh nodes in each group are transmitted overdistinct channels

    丟包由於網路阻塞路由延遲以及從高容量網路向低容量網路交換等和通道失效由於衰落效應和突發錯誤等使得在internet和無線通道上壓縮視頻數據的可靠傳輸成為新的研究課題。
  7. Underwater acoustic communications ( uwa ) are made difficult by the combined effect of multipath propagation and high temporal and spatial variability of the channel conditions. the fading which was caused by multipath propagation was one of the main factors influencing the performance of underwater acoustic communication systems

    水聲通道中廣泛存在的多徑傳播效應是水聲通信所面臨的主要障礙之一，由多徑所產生的信號衰落效應是影響水聲通信系統性能的主要因素之一。
  8. In this paper, we discuss the principle of mimo - ofdm system based on the introduction of fading channels. furthermore, the channel estimation technique in mimo - ofdm system is investigated, with the emphasis on training sequence - based and pilot - based channel estimation methods, and also several basic and improved algorithms are given respectively. finally, the analysis and comparison of these algorithms is made by computer simulation

    本文在分析移動無線通道衰落特性的基礎上，闡述了mimo - ofdm系統的基本原理，並圍繞該系統中通道估計這一關鍵技術，深入研究了基於訓練序列和基於導頻符號的兩類通道估計方法，給出幾種相應的通道估計演算法以及它們的改進演算法，最後結合matlab模擬對這些演算法的有效性和可行性進行了全面地分析與比較。
  9. With the characteristics of large ambient noise, very narrow bandwidth, low carrier frequency, great propagation latency and time - space - frequency variant multipath effect ( mpe ), the stochastic ocean channel has demonstrated the greatest complexity and difficulty for underwater acoustic wireless communications. among them multipath effect ( mpe ) is the most difficult obstacle that results in signal fading and inter - symbol interference ( isi )

    但是噪聲高、帶寬窄、載波頻率低、傳輸時延大、多途徑效應隨時間?空間?頻率變化等通道特性都會給有效、可靠的水聲通信帶來很大的麻煩，其中多途徑效應是最主要的困擾因素，它會導致信號幅度衰落和碼間干擾。
  10. 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。
  11. In current communication system, the application of dual - band dual - polarized antenna satisfies the needs of communication system ’ s upgrade, solves the problem of multipath fading, reduces the number and lowers the cost of the antennas

    在現代通信系統中，雙頻雙極化天線的應用能夠滿足通信系統的不斷升級的要求，能有效解決多徑衰落問題，能減少天線數量、降低天線成本。
  12. Spread spectrum technique, which can handle variable adverse environments, exhibits unique qualities that have a number of advantages in anti - jamming, anti - noise, reduction of multi - path interference, low power spectral density, privacy, selective addressing and code division multiplexing

    擴頻通信技術具有優越的抗干擾、抗噪音、抗多徑衰落性能，能在低功率譜密度下工作，具保密性、可多址復用和任意選址，能有效克服各種惡劣的通道特性，目前廣泛應用於移動通信、雷達、導航、測距、電力線通信等領域。
  13. On the every different application environment, this system must adopt the effective, advanced and applied technology to reject signal fading caused by mai, mutipath and near - far effects, and also to solve the corresponding problem existented at the practice communication

    在各種不同的應用環境情況下，這個系統必須採用有效的、先進的和實用的技術抑制由於多址、多徑及遠近效應引起的信號衰落，並且要不斷解決實際通信中存在的相應難題。
  14. So the acoustic wave is the only practical solution in this channel. an underwater acoustic channel is characterized as a multi - path channel due to signal reflections from the surface and the bottom of the sea. because of wave motion, the signal multi - path components undergo time - varying propagation delays that result in signal fading and inter - symbol interference ( isi )

    本文從分析淺海水聲通道的傳輸特性入手，針對多途徑效應引起的幅度衰落及碼間干擾問題，提出一種適用於水聲e - mail通信的十六進制（或八進制）數字頻移鍵控（ mfsk ）傳輸系統。
  15. The effect of multipath propagation commonly exists in the underwater acoustic channel and the fading which was caused by multipath propagation was the main influence factor of underwater acoustic communication system

    水聲通道中廣泛存在著多徑傳播效應。由多徑傳播引起的信號衰落現象是影響水聲通信系統性能的主要因素。
  16. 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。
  17. For power control of listening users, forward power control method are introduced based on full, multichannel, filtered report, and collision method etc. the full report method has redundancy report information, and its real - time performance is bad, multichannel report is introduced to improve the real - time performance, and filtered report is introduced to eliminate the redundancy information, finally the collision method introduced can not only get higher real - time performance but also diminish the redundancy information ; 2. in order to meet the requirements of making the dynamic simulation of trunking group system, the ms ’ s random move equation is brought forward, the simulation of ms ’ s distribution is done and the integrated channel model are presented ; 3. the smart predicative model of power control is introduced to overcome the delay and track the change of the complicated network, with this model, the power control ‘ s performance is greatly improved

    全匯報方法存在冗餘的匯報信息，而且實時性較差，為了改善實時性提出了多通道的匯報方式，為了改善冗餘匯報而提出了篩選法，最後介紹的碰撞法在減少冗餘信息的同時又提高了實時性;二、為了集群功率控制動態模擬的需要，提出了移動臺的隨機運動方程，進行了有關移動臺的分佈模擬，建立了綜合的通道模型;三、希望克服延時和跟蹤復雜網路環境變化，提出了功率控制的智能預測模型，通過智能預測模型可以改善功率控制的性能，著重介紹了採用神經網路的方法實現智能預測的通用模型，從而跟蹤復雜多變的無線環境，諸如慢衰落及快衰落（包括多徑衰落、多普勒效應所引起的衰落）等網路特徵，達到預測功率需求;四、採用二級正交碼和智能天線（空分多址）的方法進行組內用戶的識別，改進功率控制效果;五、話權用戶的前向和反向功率控制方法;六、對引入gota的cdma系統提出了復合容量表示方法，並作容量分析，探討有關gota系統的qos問題。
  18. The problem of signal processing for direct - sequence code - division - multiple - access ( ds - cdma ) signal over multipath frequency - selective mobile channels is considered. a new blind receiver is proposed. without the knowledge of the multiple - access interference users spreading code and the channel characteristics, the receiver achieves blind detection with prior knowledge of only the desired users spreading code and approximate timing. by using reduced rank adaptive decorrelating filter and adaptive multipath combiner which is based on decision - directed algorithm, the receiver gets the ability to combat both fading and the near - far effect at low cost. simulation results demonstrate that the proposed receiver offers high performance

    本文研究多徑頻率選擇性衰落通道下直接序列擴頻碼分多址（ ds - cdma ）信號的處理問題，提出了一種新型的盲接收機.該接收機不需預知多址干擾用戶的擴頻碼，不需預知通道參數，只需已知期望用戶的擴頻碼和粗略的定時，就可以完成用戶的盲檢測.同時，該接收機通過降維自適應去相關濾波和基於判決指導的自適應多徑合併，來獲得低成本和良好的抗衰落、抗遠近效應性能.模擬結果驗證了本文提出的接收機的優良性能
  19. In this thesis, we introduce the 3g system and the key technologies for 3g we emphasize on the technology of multi - user detection ( mud ). we analyze the performance of lmmse in various channels and prove that it can reduce the multiple access interference and the multi - path interference and it has a good ability to resist the near - far problem

    其中重點介紹了多用戶檢測技術，詳細分析了線性最小均方誤差檢測器（ lmmse檢測器）在awgn通道和衰落通道下、同異步ds - cdma系統中的性能，證明了該檢測器能夠有效地抑制多址干擾、多徑干擾，並具有良好的抗遠近效應能力。
  20. The key technologies for 3g include multi - user detection, adaptive antenna, rake receive, power control and so on. these key technologies complement each other and all of them are the focus of present research

    Cdma通信系統的關鍵技術包括有抗干擾（多用戶檢測） 、抗多徑衰落（天線分集和rake接收） 、抗遠近效應（功率控制）等，而它們之間又是相輔相成、互相補充的，均為當前研究的熱點。
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