Patent ID: 8552835

Claim:
An RFID receiver configured to decode a data signal modulated onto a carrier wave, where the phase and timing of the data signal is ambiguous, comprising: an analyzer and equalizer configured to filter an input signal; an estimation block configured to obtain a baseband representation of the modulated data signal by mixing the filtered input signal with the carrier wave; and a coherent detector configured to perform phase and timing recovery on the modulated data signal in the presence of noise and to determine a sequence of data symbols; wherein the data signal is channel coded; wherein the coherent detector comprises: a soft metric estimator; a de-interleaver; a soft input soft output (SISO) decoder; an interleaver; and a channel code decoder; wherein the soft metric estimator is configured to calculate initial soft metrics using the data signal and a fixed phase value, timing value and channel state estimated by the channel code decoder during a previous iteration; wherein the de-interleaver is configured to de-interleave an input generated by subtracting the output generated by the interleaver in a previous iteration from the initial soft metrics; wherein the SISO decoder is configured to generate updated soft metrics using the output of the de-interleaver; wherein the interleaver is configured to interleave an input generated by subtracting the output of the de-interleaver from the updated soft metrics; wherein the channel code decoder is configured to estimate a phase value, a timing value and channel state from the output of the interleaver; and wherein the coherent detector is configured to iterate until the initial soft metrics and the updated soft metrics converge.