Patent ID: 6035003
Filing Date: 2000-03-07
Classification: H04L

Abstract:
An apparatus for correcting a frequency offset of a received OFDM signal and providing the corrected OFDM signal to an OFDM demodulator through a PLL circuit formed by said apparatus, a loop filter, a voltage controlled oscillator and a derotator in OFDM receiving system, said apparatus comprising:correlation calculating means for calculating a correlation value from a predetermined reference signal and a value outputted from said OFDM demodulator; andfrequency offset estimating meansa frequency offset value generator for sequentially generating and outputting an integer or a decimal fraction in a predetermined range as a frequency offset value:a comparator for controlling the storage of a larger value of the correlation values outputted from said correlation calculating means and the output value from said frequency offset value generator used for generating correlation values stored in said temporary storing unit;a chase calculator for multiplying the output value from said frequency offset value generator by a carrier frequency interval to obtain a phase signal to be provided to said loop filter; anda controller for controlling the initializing of said frequency offset value generator, said temporary storing unit, said comparator, and said loop filter, the selecting of a value stored in said temporary storing unit as the frequency offset value, and the outputting of the selected value to said loop filter through said phase calculator.