Maximum likelihood post detection integration methods for spread spectrum systems

In the context of spread spectrum systems, this paper illustrates a novel and improved method to implement post detection integration in a code acquisition scheme in the presence of an unknown frequency error. The method is developed in the AWGN channel but is applicable to fading channels, too. The novel method is obtained through the application of the maximum likelihood criterion. The result is compared with the classic noncoherent and differential post detection integration schemes, showing significant improvements. Possible applications are in cellular CDMA networks and in satellite navigation and positioning systems.