Open Access

A Unified Approach to List-Based Multiuser Detection in Overloaded Receivers

  • Michael Krause1Email author,
  • Desmond P. Taylor1 and
  • Philippa A. Martin1
EURASIP Journal on Wireless Communications and Networking20082008:817272

DOI: 10.1155/2008/817272

Received: 31 August 2007

Accepted: 25 February 2008

Published: 6 March 2008

Abstract

A wireless communication system is overloaded when the number of transmitted signals exceeds the number of receive antennas. The presence of the resulting cochannel interference (CCI) under overload causes linear detection techniques to perform poorly. We develop a unified approach to the separation and detection of the user signals for an overloaded system using a novel iterative list-based multiuser detector. It combines a linear preprocessor with a nonlinear list detector and approximates optimum joint maximum-likelihood detection at lower complexity. Complexity savings are achieved by first, exploiting the spatial separation of the users to mitigate CCI in the preprocessor stage and second, by estimating residual CCI in the following list detection stage. The proposed list detection algorithm is applied to receivers with either a uniform circular array or a uniform linear array. The preprocessor is implemented using either a special purpose spatial filter to mitigate the CCI or maximum ratio diversity combining to achieve diversity gain. Simulation results and a complexity analysis indicate that the approach is suitable for practical application.

Publisher note

To access the full article, please see PDF

Authors’ Affiliations

(1)
Department of Electrical and Computer Engineering, University of Canterbury

Copyright

© Michael Krause et al. 2008

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.