| CPC H04L 7/0016 (2013.01) [H04Q 9/00 (2013.01); H04Q 2209/60 (2013.01)] | 15 Claims |
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1. A method for radio communication of a plurality of utility meters that are installed at distributed installation locations with a data receiver, the method comprising the steps of:
receiving, at the data receiver, data from the plurality of utility meters, wherein the data is modulated on a received signal, wherein the received signal has a time-varying phase offset;
compensating for the time-varying phase offset of the received signal by using decision-directed phase tracking to provide a compensated received signal;
coherently demodulating the compensated received signal to extract the data;
modulating the extracted data to reconstruct a replica of the received signal;
estimating a phase offset prediction error based on a comparison between the compensated received signal and the replica of the received signal;
estimating a phase offset prediction error covariance based on how much an amplitude of the compensated received signal diverges from an amplitude reference value and/or based on how much the phase offset prediction error diverges from an error reference value;
providing a Kalman filter with both the estimated phase offset prediction error and the estimated phase offset prediction error covariance as inputs for the Kalman filter; and
using an output of the Kalman filter as a prediction of the time-varying phase offset in a feedback loop to compensate for the time-varying phase offset of the received signal before the compensated received signal is coherently demodulated to extract the data.
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