Methods and systems of signal cancellation/separation for use in multi-signal communication environments are provided herein. Embodiments of the present invention use a feedback-optimized multi-signal multi-stage estimator with data-aided signal parameter estimation. Embodiments of the present invention require minimal information about the received signals and can be used to separate a desired signal from an interfering signal or two desired signals received on the same frequency. In the latter case, embodiments of the present invention effectively double the capacity of the communication system. Embodiments of the present invention are suitable for environments with intentional and/or unintentional jamming or interference. System embodiments of the present invention can be used as in-line solutions that can be inserted at different points in a receive chain.