Patent ID: 7782989

Claim:
An apparatus for acquiring initial frame timing in a communication system, the apparatus comprising: a normalizer for calculating a normalized window power from powers of samples of received signal during a monitoring period; a cross power calculator for calculating a window cross power from cross powers of the samples during the monitoring period, each cross power corresponding to multiplication of two of the samples; a divider for dividing the window cross power by the normalized window power and outputting a metric for a sample corresponding to the monitoring period; and a peak-value detector for detecting a maximum value sample among metrics for received signal samples during a predetermined period, the metrics being calculated by shifting the monitoring period, wherein a sample next to the sample searched by the peak-value detector is determined as a starting point of a frame, and wherein the normalized window power An is calculated by: A n = 1 2 ⁢ ∑ i = 0 N ⁢ {  x n + i  2 +  x n + i + m  2 } where n denotes a natural number corresponding to a starting position of the monitoring period, X n+i denotes an i-th sample within a window, the window being within the monitoring period, (N+1) is a size of the window, and in is a sample size.