• 作者： 吳國棟; 曹順安
• 作者服務機構： 中正大學電機工程研究所
• 中文摘要： 本論文主旨在於研究非同步直接序列展頻多工存取系統於使用單一或複用信號後，經過中神衰減頻道的平均錯誤機率。運用高斯積分法，並且利用自我干擾與多工存取干擾的多元積分值，可將所需信號在固定強度下的條件錯誤機率求出。平均錯誤機率為條件錯誤機率的期望值可以利用梯形積分法算出。當使用單一信號時，將對中神分佈機率作期望值運算，於複用信號狀況下，則需將其分佈函數求出，以計算平均錯誤機率。金語碼長度為127與255，可用來比較系統在單一與2複用信號下的效能。複用信號可以將平均機率改進，並可將同時使用系統的人數增加甚多。
• 英文摘要： Average error probability for asynchronous direct sequence spread spectrum multiple access communicationsthrough slow nonselective Nakagami fading channels is evaluated for nondiversity and diversity receptions. Using theGauss quadrature rule, the moments of the self-interference and the multiple access interferences are used to evaluatethe conditional error probability conditioned on a fixed fading amplitude of the desired signal. Average errorprobability, which is the expected value of the conditional error probability, is evaluated by trapezoidal integration.The pdf of the desired signal is Nakagami m-distributed for nondiversity reception. For diversity reception, the pdfof the desired signal is evaluated for selection diversity. Comparisons between the nondiversity DS-SSMA system andthat of the diversity system are shown for Gold code of codelength 127 and 255. Diversity can improve the averageerror probability performance by an order of magnitude, and the number of simultaneous users can be increasedsignificantly.
• 中文關鍵字： spread spectrum; fading channel; diversity
• 英文關鍵字： --