Patent ID: 8233576

Claim:
An apparatus for synchronization in a packet-based digital communication system that includes at least two communicating devices operating as a piconet, comprising: an hierarchical cross-correlator (H-Xcorr) module to accept an input signal comprising an hierarchical synchronization sequence having a fixed length and to output a first correlated sequence therefrom; and a detector including a second stage auto-correlator module to receive the first correlated sequence and output {circumflex over (f)}(m) as a second correlated sequence thereof delayed by the fixed length and determine from said second sequence if the input signal includes a valid preamble; wherein the second stage auto-correlator module comprises a peak computation module to compute a peak of the second correlated sequence, the peak computation module being configured to compute a frequency error based on an angle of the peak of the second correlated sequence, and compute a peak of as the peak of |{circumflex over (f)}(m)| 2 the sum of the energy of the impulse response of a channel over a window Z, where Z is a number of samples not greater than a delay spread of the channel.