Patent ID: 7372893

Claim:
A method for compensating for phase distortions in a base station of an OFDMA (orthogonal frequency division multiple access) based cellular system, comprising: (a) receiving OFDM (orthogonal frequency division multiplexing) symbols from a plurality of mobile stations; (b) grouping the plurality of the mobile stations according to a predetermined duration of time, and generating a reference timing signal for each group and relative delay times among the mobile stations; (c) canceling a symbol guard interval using the reference timing signal, and performing an FFT (fast Fourier transform) process on the OFDM symbols; (d) dividing the OFDM symbols that have undergone FFT processing into subchannel groups of the mobile stations; (d) restoring phases of the OFDM symbols divided into subchannel groups based on the estimation of the relative delay times among the mobile stations; and (e) performing channel estimation and equalization on the restored OFDM symbols for each mobile station to thereby perform a demodulation process.