Patent ID: 7899107

Claim:
A system, comprising: a differential demodulation module that (i) differentially demodulates modulated signals and (ii) generates corresponding differentially demodulated signals; and a cross-correlation module that receives said differentially demodulated signals, generates cross-correlation values by cross-correlating states of X symbols in said differentially demodulated signals with corresponding states of X predetermined symbols in each of Y preamble sequences, and determines whether one of said Y preamble sequences is present in said modulated signals based on said cross-correlation values, where X and Y are integers greater than 1, and wherein said cross-correlation module comprises: a state detection module that detects said states of said X symbols in said differentially demodulated signals, where each of said X symbols has one of a first state and a second state; and a summing module that (i) receives said Y preamble sequences and (ii) generates said cross-correlation values by generating X sums for each of said Y preamble sequences by adding each of said states of said X symbols with said corresponding states of said X predetermined symbols in each of said Y preamble sequences.