Symbol estimation methods and apparatuses

摘要

A novel symbol estimation method produces intersymbol interference free symbols by detecting interfering symbols in an interfering channel. A channel estimate is refined for additional improvements. The method can lends itself as a serial or parallel algorithm implementation. The symbol estimation method includes using an initial estimate of received symbols and calculating a refined estimate of the received symbols using a channel estimate. The refined estimate is calculated by performing parameterization of intersymbol interference by symbols other than the symbol being refined and selecting a refined value for the symbol being refined by evaluating an optimization function. Symbol estimates are refined in multiple iterations, until a predetermined iteration termination criterion is met. Parameterization of ISI contribution of other symbols results in reduced computation by reducing total number of unknown variables in the refinement operation.

主权项

1. A symbol estimation method implemented at a receiver, comprising:
calculating, based on an estimate of a communication channel and an initial estimate of a set of received symbols, a refined estimate of the set of received symbols, by performing, for each symbol in the set of received symbols, refinement operations comprising: parameterizing, for the symbol, a contribution to intersymbol interference (ISI) by the remaining symbols in the set of received symbols;
selecting a refined estimated value for the symbol by evaluating an optimization function using the estimate of the communication channel and one or more symbol values from the initial estimate of the set of received symbols; andcomputing a log-likelihood value for the selected refined estimated value for the symbol based on, at least in part, the contribution of ISI by the remaining symbols in the set of received symbols and the estimate of the communication channel; wherein the set of receive symbols comprise two possible values and wherein, in the refinement operation of selecting the refined estimate value, the evaluating the optimization function comprises evaluating a hyperbolic tan function.