Patent ID: 7366087

Claim:
A delta-predicted frequency offset compensation apparatus applied to a communication system which uses an orthogonal frequency division multiplexing (OFDM) using a plurality of orthogonal sub-carrier waves, comprising: an offset estimating means for receiving a signal from the communication system and, based on an estimation period and an estimation algorithm, estimating a frequency offset value which is normalized in the sub-carrier waves; a feedback controlling means for outputting a compensation value for offset compensation through a feedback loop by considering the estimated frequency offset value and a frequency offset delta, the frequency offset delta scaled by a factor involving the estimation period and a delay interval of the feedback loop, the scaled frequency offset delta compensating for a feedback delay introduced by the feedback loop; an offset compensation signal outputting means for outputting an offset compensation signal having a form of sine and cosine based on the compensation value transmitted from the feedback controlling means; a phase rotating means for shifting the phase of the signal inputted to the communication system with the offset compensation signal outputted from the offset compensation signal outputting means by a frequency offset corresponding to the input signal to compensate a symbol for the frequency offset; and wherein the feedback controlling means estimates the frequency offset value of the symbol whose offset is not estimated by using a previously estimated offset value, even though the offset value is not estimated by the offset estimating means, and wherein the feedback controlling means outputs the compensation value for frequency offset compensation.