Single antenna interference cancellation: iterative semiblind algorithm and performance bound for joint maximum-likelihood interference cancellation

In the first part, an iterative receiver for joint channel estimation and cochannel interference cancellation suitable for time-division multiple-access (TDMA) cellular radio systems is proposed. The receiver is based on joint maximum-likelihood sequence estimation (JMLSE). It is blind with respect to the data of the interfering users but training-based with respect to the data of the desired user and is therefore referred to as semiblind. 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 receive antenna. No knowledge on the burst structure of the interferer is used. Hence, the proposed receiver is suitable for (but not restricted to) the downlink in asynchronous networks. The proposed receiver is able to operate at a signal/interference ratio of 0 dB in asynchronous GSM/GPRS networks given a single dominating interferer. Furthermore, the results indicate that with proper interference cancellation it is not necessary to synchronize GSM/GPRS networks. In the second part, a lower bound on the bit error probability for joint maximum-likelihood sequence estimation in the presence of cochannel interference (CCI) and intersymbol interference (ISI) is presented. This lower bound is valid for an arbitrary number of interferers.