1. A method for estimating channel data bit probabilities of a multi-channel signal received through a communication channel comprising: summing a conditional bit probability conditioned on an observation of the multi-channel signal and a hypothetical channel data pattern by summing over a subset of hypothetical channel data patterns to obtain a channel data bit probability summation; and selecting the subset of hypothetical channel data patterns using a Markov chain Monte Carlo simulation to stochastically select the subset of hypothetical channel data patterns corresponding to dominant conditional bit probability terms in the channel data bit probability summation.