Patent ID: 7668246

Claim:
An orthogonal frequency division multiplexing (OFDM) demodulator, comprising: a fast Fourier transformation (FFT) calculation block which subjects an OFDM signal to FFT processing on a received OFDM signal; and a correction block which corrects a common phase error (CPE) of the transformed OFDM signal, wherein the FFT calculation block includes: an output shuffle memory which receives output values resulting from the FFT processing of the received OFDM signal, the output shuffle memory storing reordered output values; continual pilot (CP) location memory which stores locations of reordered CPs that correspond to the reordered output values; and a switch which transfers at least one output value resulting from the FFT processing of the received OFDM signal, for each reordered CP location of a current OFDM signal symbol to the correction block, based on an output address received from the CP location memory, and wherein the correction block includes: a CP memory which stores the output value transferred by the switch for each reordered CP location of the current symbol, the CP memory also storing output values of a previous OFDM signal symbol therein; a complex conjugate multiplier which multiplies the output value stored in the CP memory resulting from the FFT processing of the received OFDM signal by a corresponding output value resulting from the FFT processing of the previous symbol to determine phase differences between the current and previous OFDM signal symbols; a phase detection and accumulation block which detects and accumulates average phase values of one or more symbols of the OFDM signal based on the determined phase differences to provide a phase detection and accumulation block output; and a phase rotator which corrects a CPE of the symbols of the OFDM signal by rotating an output from the FFT calculation block in an opposite direction, based on the phase detection and accumulation block output.