DocumentCode :
1147675
Title :
A Systematic Approach to Multistage Detectors in Multipath Fading Channels
Author :
Cottatellucci, Laura ; Müller, Ralf R.
Author_Institution :
Forschungszentrum Telekommunikation Wien, Vienna, Austria
Volume :
51
Issue :
9
fYear :
2005
Firstpage :
3146
Lastpage :
3158
Abstract :
We consider linear multistage detectors with universal (large system) weighting for synchronous code-division multiple access (CDMA) in multipath fading channels with many users. A convenient choice of the basis of the projection subspace allows a joint projection of all users. Taking advantage of this property, the complexity per bit of multistage detectors with universal weights scales linearly with the number of users on the uplink CDMA channel, while other known multistage detectors with universal weights and different bases of the projection subspace keep the same quadratic complexity order per bit as the linear minimum mean-square error (LMMSE) detector. We focus on the design of two kinds of detectors with linear complexity. The detector of Type I is obtained as an asymptotic approximation of the polynomial expansion detector proposed by Moshavi The detector of Type II has the same performance as the multistage Wiener filter (MSWF) in large systems. Additionally, general performance expressions for large systems, applicable to any multistage detector with the same basis of the projection subspace (e.g., linear parallel interference canceling detectors), are derived. As a by-product, the performance analysis disproves the widespread belief that the MSWF and the polynomial expansion detector are equivalent. We show that, in general, the MSWF outperforms the latter one and they are equivalent only asymptotically in the case of equal received powers.
Keywords :
Wiener filters; code division multiple access; fading channels; least mean squares methods; matrix algebra; multipath channels; multiuser detection; polynomials; spread spectrum communication; CDMA; LMMSE; MSWF; Type-I; Type-II; linear minimum mean-square error detector; linear multistage detectors; multipath fading channels; multistage Wiener filter; multiuser detection; polynomial expansion detector; random matrix; random spreading; synchronous code-division multiple access; universal weighting; Detectors; Fading; Interference; Multiaccess communication; Multiuser detection; Performance analysis; Polynomials; Real time systems; Signal processing algorithms; Wiener filter; Asymptotic weight; code-division multiple-access (CDMA) system; multipath fading channel; multistage Wiener filter (MSWF); multistage detector; multiuser detection; polynomial expansion detector; random matrix; random spreading;
fLanguage :
English
Journal_Title :
Information Theory, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9448
Type :
jour
DOI :
10.1109/TIT.2005.853298
Filename :
1499047
Link To Document :
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