Maximum likelihood sequence estimation from the lattice viewpoint

The conventional maximum likelihood sequence estimator using the Viterbi algorithm has a time complexity of O(m/sup nu +1/) operations per symbol and a space complexity of O( delta m/sup nu /) storage elements, where m is the size of input alphabet, nu is the length of channel memory and delta is the truncation depth. The author proposes a new sequence estimator for a pulse amplitude modulation system, which has the following desired properties: its expected time complexity grows as delta /sup 2/, as SNR to infinity ; its space complexity grows as delta ; its error performance is effectively optimal for moderate-to-large values of m. Simulation results for an example channel are also presented.<
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