Patent ID: 7720177

Claim:
In a receiver, a method of locating a known sequence of symbols within a transmitted sequence of symbols comprising: forming one or more first values from one or more symbols within a portion or more of the transmitted sequence, each of the one or more first values representing an estimated difference in phase between first and second symbols within the transmitted sequence that are offset from one another; providing one or more second values formed from one or more symbols within the known sequence, each of the one or more second values representing an estimated difference in phase between first and second symbols within the known sequence that are offset from one another; forming a statistic from the one or more first values and the one or more second values, wherein the statistic is computed as one of A n 2 +B n 2 , |A n |+|B n |, and max(|A n |, |B n |), where A n = ∑ n = 0 N - k - 1 ⁢ ⁢ Re ⁡ ( X n ) × Re ⁡ ( Y n ) ± Im ⁡ ( X n ) × Im ⁡ ( Y n ) , ⁢ B n = ∑ n = 0 N - k - 1 ⁢ ⁢ Re ⁡ ( X n ) × Im ⁡ ( Y n ) ± Im ⁡ ( X n ) × Re ⁡ ( Y n ) , where X n is one of the one or more first values, Yn is one of the one or more second values, N is an integer of two or more, k is an integer of one or more that is less than N, Re is an operator that returns the real part of a complex symbol, and Im is an operator that returns the imaginary part of a complex symbol; and determining that the portion or more of the transmitted sequence is the known sequence if the one or more estimated differences in phase represented by the one or more first values are substantially equal to corresponding ones of the one or more estimated differences in phase represented by the one or more second values and identifying a frame end using the known sequence.