1. A method of estimating noise variance comprising: a) estimating a true noise variance using a long-term data aided algorithm; b) estimating an interference variance using a short-term data aided algorithm; c) determining an interference hypothesis based on comparing the noise and interference variance estimations; d) computing a variance for a decision directed noise sample; e) converting the variance for the decision directed noise sample to a true noise variance per packet; f) converting the variance for the decision directed noise sample to a true noise variance per symbol; g) determining an interference hypothesis based on the true noise variance estimation per symbol and the true noise variance estimation per packet; h) determining the presence of interference based on a comparison of the true noise variance per packet, the true noise variance per symbol, and each hypothesis; i) computing the long-term noise variance; and j) using the long-term noise variance in place of the variance for a decision directed noise sample for a subsequent determination of the presence of interference.