Patent ID: 7054396

Claim:
An apparatus comprising: a) a compensation circuit adapted to receive input samples from a received multipath signal and compensate the input samples using secondary signal estimates to form compensated samples; b) a hard-decision circuit adapted to receive the compensated samples and determine a nominal phase value for each input sample, wherein said hard-decision circuit outputs a selected one from a defined set of nominal phase values as the nominal phase value; c) a buffer circuit adapted to receive the nominal phase value from said hard-decision circuit and maintain a running sequence of past nominal phase values in successive buffer positions corresponding to successively greater sample time offsets with respect to the current input sample; d) a buffer interface circuit adapted to receive path delay information corresponding to a secondary path signal and provide a selected past nominal phase value, one or more early nominal phase values, and one or more later nominal phase values by retrieving the past nominal phase value currently held in one of said buffer positions corresponding to a sample time offset equal to the received path delay information and further retrieving the one or more early nominal phase values from one or more of said buffer positions which precede said buffer position corresponding to the sample time offset and the one or more later nominal phase values from one or more of said buffer positions which follow said buffer position corresponding to the sample time offset; and e) an estimation circuit comprising i) memory and calculation logic adapted to receive the selected past nominal phase value selected from said buffer interface circuit, receive and store magnitude and phase information corresponding to the secondary path signal in the received multipath signal, and produce an unscaled secondary signal estimate for a current input sample based on the magnitude and phase information and the past nominal phase value derived from prior input samples; ii) scaling logic adapted to produce a scaling factor based on the one or more early nominal phase values and the one or more later nominal phase values preceding and following said selected past nominal phase value; and iii) multiplication logic adapted to combine the unscaled secondary signal estimate and the scaling factor to produce a current secondary signal estimate; wherein said apparatus is operative to remove secondary path signal interference from the input samples for output as compensated samples to an associated communications system based directly or indirectly upon successive current secondary signal estimates.