Method and apparatus for digital communication in the presence of closely spaced adjacent channels

A method of detecting the digital bits of at least one desired signal from a communications medium having overlapping communications channels, comprising the steps of:

• a.) receiving at least one desired signal and at least one undesired interfering signal;
• b.) digitizing the at least one desired signal and the at least one undesired interfering signal;
• c.) determining initial parameter estimations of the at least one desired signal and the at least one undesired interfering signal;
• d.) initially separating the at least one desired signal and the at least one undesired interfering signal into an estimated at least one desired signal and an estimated at least one undesired interfering signal, respectively;
• e.) subtracting the estimated at least one undesired interfering signal from the at least one desired signal and the at least one undesired interfering signal to produce an updated desired signal;
• f.) redetermining the parameter estimations of the updated desired signal and the spectral estimations of the undesired interfering signal;
• g.) repeating steps e. and f.
• wherein the step of determining initial spectral estimations further includes the steps of:
• estimating the digital timing of the at least one desired signal and the at least one undesired interfering signal;
• estimating the frequency of the at least one desired signal and the at least one undesired interfering signal;
• estimating the complex amplitude of the at least one desired signal and the at least one undesired interfering signal;
• and
• estimating the channel impulse response of the at least one desired signal and the at least one undesired interfering signal.

A communication receiver capable of detecting the information bits of each of one or more digital communication signals from a plurality of overlapping frequency bands in the presence of adjacent channel interference, the receiver comprising:

• a demodulator including an analog to digital convertor producing a digital version from a set of overlapping frequency bands;
• a processor unit connected to the demodulator for receiving the digital version of the set of overlapping frequency bands and for detecting the information bits of one or more desired digital communication signals, the processor unit further includes:
• spectral estimator process initially determining timing, frequency and power level parameter estimations of the digital version of each of the overlapping frequency bands;
• initialization process receiving the parameter estimations, determining the sequence in which the digital version of each of the overlapping frequency bands is processed, and dividing the one or more desired digital communication signals and the adjacent channel interference into clusters of closely spaced signals;
• signal separator process receiving the parameter estimations and subtracting reconstructed adjacent clusters of closely spaced signals from the digital version of the set of overlapping frequency bands;
• and
• detection and reconstruction process detecting the information bits from the clusters of closely spaced signals and producing therefrom the one or more desired digital communication signals.