Burst mode equalization: optimal approach and suboptimal continuous-processing approximation

We consider a transmission by burst where the data are organized and sent by bursts. At each end of the burst of data, a sequence of symbols is assumed known, and the channel considered as constant over the burst duration. The optimal structure of the burst mode equalizers is derived. The class of linear and decision feedback equalizers is considered, as well the class of ISI cancelers that use past but also future decisions: for each class of equalizers the MMSE, the unbiased MMSE and the MMSE zero forcing versions are derived. Unlike in the continuous-processing mode, the optimal burst mode filters are time varying. The performance of the different equalizers are evaluated and compared to each other in terms of SNR and probability of error: these measures depend on the position of the estimated symbol and on the presence of known symbols. Finally, we show that, by choosing correctly the number and position of the known symbols, (time-invariant) continuous-processing filters applied to burst mode can be organized to give sufficiently good performance, so that optimal (time-varying) burst processing implementation can be avoided.