Application of joint channel and data estimation algorithms for short block detection

This paper presents studies of the expectation-maximization (EM) algorithm and its modifications for joint channel estimation and short block detection in frequency selective channels. To facilitate the EM convergence in case of short blocks, we introduce a penalized update for channel re-estimates in semi-blind detection. For channels with intersymbol interference, we suggest a simple method to improve accuracy of channel re-estimates (channel model inverse) that may be embedded into EM-based detectors. Application of the EM-based detectors for schemes with transmitting diversity in EDGE (enhanced data rates for GSM evolution) provides more than 1dB gain