Averaged stochastic gradient algorithms for adaptive blind multiuser detection in DS/CDMA systems

Author

Krishnamurthy, Vikram

Author_Institution

Dept. of Electr. & Electron. Eng., Melbourne Univ., Parkville, Vic., Australia

Volume

48

Issue

1

fYear

2000

fDate

1/1/2000 12:00:00 AM

Firstpage

125

Lastpage

134

Abstract

In this paper, we present a blind adaptive gradient (BAG) algorithm for code-aided suppression of multiple-access interference (MAI) and narrow-band interference (NBI) in direct-sequence/code-division multiple-access (DS/CDMA) systems. This BAG algorithm is based on the concept of accelerating the convergence of a stochastic gradient algorithm by averaging. This ingenious concept of averaging was invented by Polyak and Juditsky (1992)-this paper examines its application to blind multiuser detection and NBI suppression in DS/CDMA systems. We prove that BAG has identical convergence and tracking properties to recursive least squares (LMS) but has a computational cost similar to the least mean squares (LMS) algorithm-i.e., an order of magnitude lower computational cost than RLS. Simulations are used to compare our averaged gradient algorithm with the blind LMS and LMS schemes

Keywords

adaptive signal detection; code division multiple access; computational complexity; convergence of numerical methods; gradient methods; interference suppression; spread spectrum communication; stochastic processes; BAG algorithm; DS/CDMA systems; NBI suppression; adaptive blind multiuser detection; averaged gradient algorithm; averaged stochastic gradient algorithms; averaging; blind adaptive gradient algorithm; code-aided suppression; computational cost; convergence; direct-sequence/code-division multiple-access; multiple-access interference; narrow-band interference; stochastic gradient algorithm; tracking properties; Acceleration; Computational efficiency; Convergence; Interference suppression; Least squares approximation; Multiaccess communication; Multiple access interference; Multiuser detection; Narrowband; Stochastic processes;

fLanguage

English

Journal_Title

Communications, IEEE Transactions on

Publisher

ieee

ISSN

0090-6778

Type

jour

DOI

10.1109/26.818880

Filename

818880