Demodulation methods and apparatus for a multi-stage SLI demodulator are disclosed. Residual signals from each demodulation stage are modeled as finite sets of unresolved signals and a new metric is introduced for use in search of best candidate symbol estimates. The metric may be evaluated based on a probability distribution function of the residual signals or a probability mass function of the unresolved signals. The metric may also be approximated by the sum of a conventional Euclidean metric and a correction metric. The best candidate symbol estimates generated from each stage of the multi-stage SLI demodulator are summed to form cumulative symbol estimates.