Patent ID: 6363106
Filing Date: 2002-03-26
Classification: H04B,H04L

Abstract:
In a receiver in a spread spectrum communication system, a device for despreading an Offset QPSK (OQPSK) spread data signal, the OQPSK spread data signal being spread by a complex pseudonoise sequence and divided into an inphase and a quadrature phase component, the pseudonoise sequence being divided into chip periods, the device for despreading upon reception of the OQPSK spread data signal in the receiver comprising:means for generating samples of the quadrature and the inphase components; means for downsampling the quadrature and the inphase components to provide two complex samples of each of the quadrature and the inphase components per chip period, termed the odd and even complex samples; delaying means for delaying at least one of the odd complex samples or the even complex samples of the downsampled signals of the inphase component; adding means for adding the delayed downsampled signal of the inphase component to a non-delayed downsampled signal of the inphase component; means for performing a complex correlation between a segment of the samples corresponding to at least one data symbol period of the OQPSK spread data signal and a corresponding segment of the complex pseudonoise sequence; and means for generating correlation values based on the results of the complex correlation.