Effects of Multiple Access Interference in a Multi-Rate SSMA System

Motohiro ICHIBA  Masaaki KATAYAMA  Takaya YAMAZATO  Akira OGAWA  

IEICE TRANSACTIONS on Communications   Vol.E79-B    No.9    pp.1333-1338
Publication Date: 1996/09/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Personal Communications)
Category: CDMA and multiple access technologies
wireless multimedia communication systems,  multirate signal,  spread spectrum,  different processing gains,  crosscorrelation,  

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In this study, we analyze the system which simultaneously transmits spread-spectrum signals with different processing gains. The main purpose of this study is to give an analytical framework that describes the influence of the interfering signals with different processing gains. For this purpose, we define a crosscorrelation function between the spreading sequences with different code lengths, and discuss the effects of interaction between the signals. As the results, we show that the power of the interference component after despreading procedure, the power ratio of the desired to undesired components, and thus the bit error rate are not constant but vary symbol by symbol.