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Open Access

Iterative PDF Estimation-Based Multiuser Diversity Detection and Channel Estimation with Unknown Interference

EURASIP Journal on Advances in Signal Processing20052005:521373

Received: 8 October 2003

Published: 15 May 2005


The equivalent diversity order of multiuser detector employing multiple receive antennas and minimum mean squared error (MMSE) processing for frequency-selective channels is decreased if it aims at suppressing unknown cochannel interference (UCCI) while detecting multiple users' signals. This is an unavoidable consequence of linear processing at the receiver. In this paper, we propose a new multiuser signal detection scheme with the aim to preserve the detector's diversity order by taking into account the structure of the UCCI. We use the fact that the structure of the UCCI appears in the probability density function (PDF) of the UCCI plus noise, which can be characterized as multimodal Gaussian. A kernel smoothing PDF estimation based receiver is derived. The PDF estimation can be based on training symbols only (noniterative PDF estimation) or on training symbols as well as feedback from the decoder (iterative PDF estimation). It is verified through simulations that the proposed receiver significantly outperforms the conventional covariance estimation in channels with low frequency selectivity. The iterative PDF estimation significantly outperforms the noniterative PDF estimation-based receiver with minor training overhead.

Keywords and phrases

turbo equalizationcochannel interferencePDF estimation

Authors’ Affiliations

Centre for Wireless Communications, University of Oulu, Oulu, Finland


© Veselinovic et al. 2005