Patent ID: 7587016

Claim:
An apparatus, comprising: a first symbol timing recovery module that is operable to: calculate a modified correlation function that varies as a function of each sample of a first plurality of samples of a first moving window and each sample of a second plurality of samples of a second moving window of an OFDM (Orthogonal Frequency Division Multiplexing) packet, wherein the modified correlation function is normalized with respect to a first power corresponding to the first moving window and a second power corresponding to the second moving window; compare the modified correlation function to a symbol timing recovery threshold; identify a peak value of the modified correlation function when the modified correlation function exceeds the symbol timing recovery threshold and when the modified correlation function is substantially non-increasing; identify a mid-point of a decreasing region of the modified correlation function that, when biased by a predetermined amount, is less than the peak value of the modified correlation function; identify an end-point of the decreasing region of the modified correlation function that, when scaled by a predetermined scaling factor, is less than the peak value of the modified correlation function; compare the first power corresponding to the first plurality of samples of the first moving window to a first power threshold; and compare the second power corresponding to the second plurality of samples of the second moving window to a second power threshold; and a choice logic module that is operable to: receive a first symbol timing recovery signal, corresponding to a first stream of a plurality of receive streams, from the first symbol timing recovery module; receive a second symbol timing recovery signal, corresponding to a second stream of the plurality of receive streams, from a second symbol timing recovery module that is also implemented within the apparatus; receive a first carrier detect signal, corresponding to the first stream of the plurality of receive streams, from a first carrier detect module that is also implemented within the apparatus; receive a second carrier detect signal, corresponding to a second stream of the plurality of receive streams, from a second carrier detect module that is also implemented within the apparatus; and based on the first carrier detect signal and the second carrier detect signal, select either the first symbol timing recovery signal, the second symbol timing recovery signal, or a non-symbol timing recovery signal for each of the first stream and the second stream of the plurality of receive streams.