DocumentCode :
2627832
Title :
Synchronous CDMA Based on the Cyclical Translations of a CAZAC Sequence
Author :
Carni, E. ; Spalvieri, A.
Author_Institution :
Dipartimento di Elettronica e Informazione, Politecnico di Milano, Milan
fYear :
2005
fDate :
7-7 Sept. 2005
Firstpage :
442
Lastpage :
446
Abstract :
We introduce a new class of code sequences for synchronous CDMA, having in mind application to the downlink of cellular systems. The code that we propose is made by all the cyclical translations of what is called in the literature a CAZAC sequence, for example a Frank-Zadoff sequence. We show that, when the transmission channel is affected by multipath and noise, the proposed code allows multiuser interference to become cyclic intersymbol interference, provided that a cyclic prefix is appended to the multiplexed vector. Noticeably, the memory of the finite state machine that describes the ISI model is equal to memory of the multipath channel. The main advantage of our proposed system is that optimal detection is obtained by the classical Viterbi algorithm, which is much easier to implement than the optimal multiuser detector of classical CDMA schemes. Another advantage of our scheme is that it leads naturally to a signal processing architecture similar to that of OFDM systems, hence based on the efficient FFT/IFFT algorithm
Keywords :
cellular radio; channel coding; code division multiple access; fast Fourier transforms; finite state machines; intersymbol interference; maximum likelihood detection; multipath channels; multiuser channels; radio links; radiofrequency interference; FFT; Frank-Zadoff sequence; OFDM systems; cellular system downlink; classical Viterbi algorithm; code sequences; cyclic intersymbol interference; cyclic prefix; cyclical translations; finite state machine; multiplexed vector; multiuser interference; signal processing architecture; synchronous CDMA; transmission channel; Automata; Code division multiplexing; Detectors; Downlink; Intersymbol interference; Multiaccess communication; Multipath channels; OFDM; Signal processing algorithms; Viterbi algorithm;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Wireless Communication Systems, 2005. 2nd International Symposium on
Conference_Location :
Siena
Print_ISBN :
0-7803-9206-X
Type :
conf
DOI :
10.1109/ISWCS.2005.1547739
Filename :
1547739
Link To Document :
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