Probabilistic algorithms for blind adaptive multiuser detection

Author

Anton-Haro, Carles ; Fonollosa, José A R ; Zvonar, Zoran ; Fonollosa, Javier R.

Author_Institution

Dept. of Signal Theory & Commun., Univ. Politecnica de Catalunya, Barcelona, Spain

Volume

46

Issue

11

fYear

1998

fDate

11/1/1998 12:00:00 AM

Firstpage

2953

Lastpage

2966

Abstract

Two probabilistic adaptive algorithms for jointly detecting active users in a DS-CDMA system are reported. The first one, which is based on the theory of hidden Markov models (HMMs) and the Baum-Welch (1070) algorithm, is proposed within the CDMA scenario and compared with the second one, which is a previously developed Viterbi-based algorithm. Both techniques are completely blind in the sense that no knowledge of the signatures, channel state information, or training sequences is required for any user. Once convergence has been achieved, an estimate of the signature of each user convolved with its physical channel response (CR) and estimated data sequences are provided. This CR estimate can be used to switch to any decision-directed (DD) adaptation scheme. Performance of the algorithms is verified via simulations as well as on experimental data obtained in an underwater acoustics (UWA) environment. In both cases, performance is found to be highly satisfactory, showing the near-far resistance of the analyzed algorithms

Keywords

Viterbi detection; acoustic signal detection; adaptive signal detection; code division multiple access; convolution; hidden Markov models; probability; pseudonoise codes; spread spectrum communication; telecommunication channels; underwater sound; Baum-Welch algorithm; DS-CDMA system; HMM; Viterbi-based algorithm; blind adaptive multiuser detection; channel response; convergence; decision-directed adaptation scheme; estimated data sequences; experimental data; hidden Markov models; near-far resistance; performance; probabilistic adaptive algorithms; simulations; underwater acoustics; user signature estimation; Adaptive algorithm; Channel state information; Chromium; Convergence; Hidden Markov models; Multiaccess communication; Multiuser detection; Performance analysis; Switches; Underwater acoustics;

fLanguage

English

Journal_Title

Signal Processing, IEEE Transactions on

Publisher

ieee

ISSN

1053-587X

Type

jour

DOI

10.1109/78.726809

Filename

726809