Patent ID: 6643344
Filing Date: 2003-11-04
Classification: H04B

Abstract:
A method of tracking a locally generated spread spectrum signal sequence, the method which comprises:correlating a received spread spectrum signal sequence with the locally generated spread spectrum signal sequence with respect to a synchronization time at a relatively earlier time and a relatively later time in an early and late interval, respectively, thereby generating correlation responses; subtracting the correlation responses from one another; controlling a clock of the locally generated spread spectrum signal sequence as a function of a result of the subtracting step for synchronizing the locally generated spread spectrum signal sequence with the received spread spectrum signal sequence corresponding to the locally generated spread spectrum signal sequence; and performing correlations based on at least two hierarchically staggered closed-loop controls with different early and late intervals, wherein an early interval of a first one of the at least two hierarchically staggered closed-loop controls has a relatively smaller early and late interval such that the early interval of the first one of the at least two hierarchically staggered closed-loop controls does not become earlier than an early interval of a second one of the at least two hierarchically staggered closed-loop controls having a relatively next-larger early and late interval, and wherein a late interval of the first one of the at least two hierarchically staggered closed-loop controls is such that the late interval of the first one of the at least two hierarchically staggered closed-loop controls does not become later than a late interval of the second one of the at least two hierarchically staggered closed-loop controls.