Algorithm and Performance Evaluation of Spread Spectrum Communication Receivers
Date Issued
2004
Date
2004
Author(s)
Chen, Ting-yao
DOI
en-US
Abstract
對於操作於頻率選擇性頻道中之上鏈非同步直序多碼分工(DS-CDMA)系統，可利用其特殊性質採用較有效率之接收機架構來降低系統複雜度。而前白化削樹(PWTP)演算法也可套用。我們提出了一種PWTP之降態修改，稱之為代表點(RP)演算法，其可進一步降低大信號星群(signal constellation)系統之複雜度。模擬結果顯示，在相同複雜度下，代表點演算法之表現優於傳統演算法。
互補分碼鍵控(CCK)是一種非線性編碼調變。在多路徑環境中，傳統等化器可能輸出無效的CCK序列。我們提出了加入限制路徑的序列估測演算法，其利用了碎碼間的特殊關係，並保證輸出有效的序列。最後，我們使用電腦模擬以比較並評估各演算法之表現。
For uplink asynchronous direct sequence code division multiple access (DS-CDMA) systems in frequency-selective channels, efficient receiver structures utilizing the special properties of the systems can be applied to lower complexity. The pre-whitening tree pruning (PWTP) algorithm can be used with the structures. We propose the representative point (RP) algorithm, which is a reduced-state modification to PWTP algorithm, to further lower the complexity when large constellations are used. Simulation shows that RP outperforms the traditional algorithm with complexity being equal.
Complementary code keying (CCK) is a nonlinear coded modulation. In multipath environment, traditional equalizers regard each chip as an independent symbol and may output invalid CCK sequences. We propose sequence estimation with restricted path (SERP) algorithm, which utilizes certain relationships between chips of CCK sequences and guarantees outputting valid sequences. Simulation is used to compare and evaluate the algorithms.
Subjects
展頻
演算法
通訊系統
Spread Spectrum
Communication System
CDMA
CCK
Type
thesis
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