BER Analysis for Multi-Carrier DS CDMA with Multi-Rate Traffic

Abbas SANDOUK  Masaaki HARADA  Hiraku OKADA  Takaya YAMAZATO  Masaaki KATAYAMA  Akira OGAWA  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E84-A   No.7   pp.1723-1731
Publication Date: 2001/07/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section LETTER (Special Section on Multi-dimensional Mobile Information Networks)
Category: 
Keyword: 
multi-rate traffic,  BER analysis,  multi-carrier DS-CDMA,  OFDM-CDMA,  

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Summary: 
In this letter, we present bit error analysis (BER) of orthogonal multi-carrier direct sequence code division multiple access (DS-CDMA) system with multi-rate (multimedia) traffic. Analysis is carried out with random signature codes for an AWGN channel. Interference in such a system is severe because all users of all media transmit over the same assigned sub-carriers. This makes the analysis difficult. In our analysis, we divide this interference into different types and carry out our analysis to obtain the BER taking into account all these types. We show that the performance of the system is improved as the number of assigned sub-carriers M increases until a limit where the improvement does not continue even when M increases more. This is because of, as we show, the interference due to other sub-carriers becomes constant even in the case of M , and the interference in a multi-rate multi-carrier system is bigger than that in a single-carrier (M=1) by a factor of π2/3.