Am. Chan et Gw. Wornell, A class of block-iterative equalizers for intersymbol interference channels: Fixed channel, IEEE COMMUN, 49(11), 2001, pp. 1966-1976
A new and efficient class of nonlinear equalizers is developed for intersym
bol interference (ISI) channels. These "iterated-decision equalizers" use a
n optimized multipass algorithm to successively cancel ISI from a block of
received data and generate symbol decisions whose reliability increases mon
otonically with each iteration. These equalizers have an effective complexi
ty comparable to the decision-feed back equalizer (DFE), yet asymptotically
achieve the performance of maximum-likelihood sequence detection (MLSD). W
e show that, because their structure allows cancellation of both precursor
and postcursor IST, iterated-decision equalizers outperform the minimum mea
n-square error DFE by 2.507 dB on severe ISI channels even with uncoded sys
tems. Moreover, unlike the DFE, iterated-decision equalizers can be readily
used in conjunction with error-control coding, making them attractive for
a wealth of applications.