Spread spectrum receiver and method for carrier frequency offset compensation in such a spread spectrum receiver

Abstract

The invention relates to a spread spectrum receiver for receiving and decoding an input signal r(k) consisting of a sequence of chips and a method for carrier frequency offset compensation in such a spread spectrum receiver. The receiver comprises a correlator for processing the input signal r(k) and providing at its output a signal y(n) which consists of a sequence of symbols; a phase rotator, coupled to an output of the correlator, for rotating the phase of the signal y(n) based on a filtered phase error signal θ(n) in order to compensate a carrier frequency offset Ω contained in the input signal r(k); a detector, coupled to an output of the phase rotator, for receiving the rotated signal z(n) and for taking a decision on the symbols and providing an output signal c(n) which is subsequently demapped to a sequence of bits; an error signal generator, coupled to the outputs of the phase rotator and the detector, for generating a phase error signal e(n) which depends on the carrier frequency offset of the input signal r(k); and a loop filter, coupled to an output of the error signal generator, for filtering the phase error signal e(n) and feeding the filtered phase error signal θ(n) to the phase rotator.