Skip to content


  • Research Article
  • Open Access

Soft-In Soft-Output Detection in the Presence of Parametric Uncertainty via the Bayesian EM Algorithm

EURASIP Journal on Wireless Communications and Networking20052005:201802

  • Received: 30 April 2004
  • Published:


We investigate the application of the Bayesian expectation-maximization (BEM) technique to the design of soft-in soft-out (SISO) detection algorithms for wireless communication systems operating over channels affected by parametric uncertainty. First, the BEM algorithm is described in detail and its relationship with the well-known expectation-maximization (EM) technique is explained. Then, some of its applications are illustrated. In particular, the problems of SISO detection of spread spectrum, single-carrier and multicarrier space-time block coded signals are analyzed. Numerical results show that BEM-based detectors perform closely to the maximum likelihood (ML) receivers endowed with perfect channel state information as long as channel variations are not too fast.


  • expectation-maximization algorithm
  • soft-in soft-out detection
  • fading channels
  • space-time coding
  • OFDM

Authors’ Affiliations

Department of Information Engineering, University of Modena and Reggio Emilia, via Vignolese 905, Modena, 41100, Italy


© Gallo and Vitetta 2005

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.