Patent ID: 8472569

Claim:
A preamble symbol timing extraction system, comprising: a preamble correlator configured to generate correlation samples by correlating symbols derived from differential phase shift keyed data with a correlation reference sequence; a coarse symbol timing estimator configured to, generate a coarse preamble symbol timing estimate based on the correlation samples, wherein the coarse preamble symbol timing estimate comprises a coarse timing index value that identifies coarse timing for symbol acquisition, and a fine symbol timing estimator produces a fine preamble symbol timing estimate based on the coarse timing index value and correlation samples immediately adjacent to a correlation sample corresponding to the coarse timing index value; and the fine symbol timing estimator configured to identify a coarse timing correlation sample corresponding to the coarse preamble symbol timing estimate, an early correlation sample immediately preceding the coarse timing correlation sample, and a late correlation sample immediately following the coarse timing correlation sample, and to, generate the fine preamble symbol timing estimate by combining the early correlation sample, the late correlation sample, and, optionally, the coarse timing correlation sample, the fine symbol timing estimator furthered configured to generate the fine preamble symbol timing estimate based on a difference in power of the early correlation sample and power of the late correlation sample and, wherein the fine symbol timing estimator is configured to divide the difference by a divisor selected from a group consisting of: power of the coarse timing correlation sample; magnitude of the coarse timing correlation sample; sum of power of the early correlation sample and power of the late correlation sample; sum of magnitude of the early correlation sample and magnitude of the late correlation sample; sum of weighted power of the early correlation sample and power of the late correlation sample, and weighted power of the coarse timing sample; sum of weighted magnitude of the early correlation sample and magnitude of the late correlation sample, and weighted magnitude of the coarse timing sample; and a predetermined maximum correlation value.