Patent ID: 7602835
Filing Date: 2009-10-13
Classification: H04B

Abstract:
1. A correlator configured to despread a multi-rate composite long code defining a composite length of at least N*M, where N and M are integers each greater than one, comprising: a first stage comprising: a second stage comprising: a shift register having an input coupled to an output of the first despread adder, wherein an energy profile of the shift register exhibits a peak when contents of the shift register are in proper alignment with the multi-rate composite long code; wherein the multi-rate composite long code is constructed from at least a first constituent code and a second constituent code, wherein the first constituent code defines a first length N and the second constituent code defines a second length M, wherein the second constituent code is a cover code running at a rate of 1/N; wherein the delay elements of the first plurality each delay one unit of time and the delay elements of the second plurality each delay N units of time; wherein the first stage operates at a rate X and the second stage operates at a rate X/N; wherein N is not equal to M, and X is an integer greater than one.