Adaptive equalization and diversity combining for a mobile radio channel

The feasibility of a digital cellular radio (DCR) system which uses a jointly adaptive decision-feedback equalizer and diversity combiner is discussed. The current estimates of the channel impulse response (CIR) are utilized at each diversity branch to compute the receiver parameters periodically. A block-adaptive strategy that computes the time-varying CIR by interpolating a set of CIR estimates obtained through periodic training is proposed. Despite incurring some inherent processing delay and throughput reduction, this interpolation strategy is shown to have the advantage of immunity to decision errors which would quite likely occur during a deep fade. It is shown that the system performance is limited mainly by the CIR estimation caused by imperfect training which is manifest in the form of an irreducible bit error rate at high signal-to-noise ratios (SNRs)