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Abstract

Estimates of both the communication channel impulse response coefficients and a received signal carrier frequency offset are generated simultaneously without either estimation interfering with or hampering of the other estimation. This is realized in an embodiment of the invention by utilizing both received symbols known to the receiver during a training sequence and a received signal to generate simultaneously an estimate of the impulse response coefficients of the communication channel and an estimate of the received signal carrier frequency offset. In one embodiment of the invention a first estimator and a second estimator are employed to generate the communication channel impulse response coefficients and the received signal carrier frequency offset, respectively. Specifically, in the first estimator, (a) data symbols in the training sequence, (b) the magnitude of the received signal, (c) the magnitude of an estimate for the received signal and (d) a step size based on a learning coefficient are employed in a first prescribed relationship to generate the communication channel impulse response coefficients. Simultaneously, in the second estimator, a second prescribed relationship between the received signal and its estimate is employed to generate the received signal carrier frequency offset. In another embodiment of the invention, the estimation process is begun utilizing the first estimator to generate the communication channel impulse response coefficients and the second estimator to generate the received signal carrier frequency offset, with the latter being monitored. When the estimated frequency offset falls below a predetermined threshold value, the generation of the communication channel impulse response coefficients is switched to use a third estimator, for example, a least mean squares (LMS) estimator, while generation of the received signal carrier frequency offset estimation continues simultaneously.

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First Claim