Channel estimation and equalization for narrow-band TDMA mobile radio

The performance of a joint estimation/equalization technique for the mobile radio channel is investigated. The transmission format follows GSM Recommendations for the pan-European digital mobile radio. Channel estimation is performed via correlation techniques, while channel equalization is achieved by means of maximum likelihood sequence estimation. Theoretical bounds on the bit error rate are derived, and their dependence on the channel model is discussed. Particular attention is devoted to analysis of the minimum Euclidean distance of sequence error events as a function of the number of paths as well as amplitude, phase shift, and delay of indirect paths. The capability of the MLSE receiver to cope with most propagation conditions is shown. The impact of an imperfect (i.e. noisy) channel impulse response estimate is evaluated, revealing a bit-error-rate degradation of a few decibels that was quite independent of the particular value of signal-to-noise ratio at the receiver. Extensive simulation results are presented to validate the theory