In this paper, an iterative receiver for joint channel estimation and cochannel interference cancellation suitable for time-division multiple-access cellular radio systems is proposed. The receiver is blind with respect to (w.r.t.) the data of the interfering users and training-based w.r.t the data of the desired user and is therefore referred to as semi-blind. As opposed to concurrent receiver structures, where the number of receiving antennas must exceed the number of cochannel interferers, the proposed receiver is suitable for just one receiving antenna, i.e., the proposed receiver is also suitable for the downlink. A tight analytical lower bound on the bit error probability for joint maximum-likelihood sequence estimation in the presence of cochannel interference and intersymbol interference is presented. Monte Carlo simulation results indicate that with just one receiving antenna and no oversampling the proposed receiver is able to achieve a raw bit error rate of 10-2 even at a signal-to-interference ratio of 0 dB in asynchronous GSM/EDGE networks given a single dominant interferer.