Patent ID: 8879675
Filing Date: 2014-11-04
Classification: H04L

Abstract:
1. A synchronization system for initial setup of phases of local oscillators in a wireless receiver of a communication system, wherein the communication system is characterized by transmission of data packets having a predetermined preamble consisting of M identical sections of L symbols followed by a single section of the same kind, multiplied by −1, and wherein the wireless receiver is operative to perform decimation in an RF demodulator, comprising: A. a twofold correlator having an input for receiving a stream of complex input symbols from the RF demodulator, a symbols correlation output, and a slopes correlation output, and including a coefficients memory for storing a SymbolsCoefficients[k] coefficients set and SlopesCoefficients[k] coefficients set, where 0≦k<L, wherein said twofold correlator is B. an accumulator having a symbols correlation input coupled to the symbols correlation output of the twofold correlator, a slopes correlation input coupled to the slopes correlation output of the twofold correlator, an accumulated symbols correlation output and an accumulated slopes correlation output, wherein said accumulator is operative to: C. a multiplier having a first multiplier input coupled to the accumulated symbols correlation output of the accumulator, and a second multiplier input coupled to the symbols correlation output of the twofold correlator through a series circuit operative multiply the signal from the symbols correlation output of the twofold correlator by −1 and perform a conjugate transform thereon and apply a resultant multiplier signal to the multiplier output, D. a threshold comparator having a threshold input coupled to the multiplier output and a threshold output, wherein the threshold comparator is operative to produce a pulse at the threshold output when the resultant multiplier signal exceeds a predetermined threshold, E. a carrier phase former having a carrier phase input coupled to the accumulated symbols correlation output of the accumulator, and a carrier phase correction output, wherein the accumulated symbols correlation signal is a complex value having a real part and an imaginary part, and wherein the carrier phase former is operative to generate a carrier phase correction signal and apply the carrier phase correction signal to the carrier phase correction output, wherein the carrier phase correction signal corresponds to the arctangent of a ratio of the real part of the accumulated symbols correlation signal to the imaginary part of the accumulated symbols correlation signal, F. a clock phase former having a first clock phase input coupled to the accumulated slopes correlation output of the accumulator, a second clock phase input coupled to the carrier phase correction output, and a clock phase correction output, wherein the clock phase former is operative to generate a clock phase correction signal and apply the clock phase correction signal to the clock phase correction output.