Timing acquisition and mode and guard detection for OFDM transmission

Techniques for detecting mode and guard length and estimating timing offset for an OFDM transmission are described. Multiple hypotheses for different combinations of mode and guard length that might have been used for the OFDM transmission are evaluated. For each hypothesis, correlation is performed on received samples for a hypothesized guard interval to obtain correlation results. The energy of the hypothesized guard interval is determined. A first metric is derived based on the correlation results and the energy. The first metric may be filtered, e.g., averaged. Noise is estimated, e.g., based on a set of elements for the filtered first metric at locations determined by an estimated timing offset for the hypothesis. A second metric is derived based on the filtered first metric and the estimated noise. The second metric for all hypotheses may be used to determine the mode, guard length, and timing offset for the OFDM transmission.