Patent ID: 7876868

Claim:
A method of reducing interference in an Orthogonal Frequency Division Modulation (OFDM) communication system comprising: at a receiver: receiving, from a transmitter, a current and a previously transmitted OFDM symbol; determining an interference contribution associated with a selected subcarrier of a plurality of subcarriers associated with the previously transmitted OFDM symbol, wherein the interference contribution results from a length of a composite channel impulse response, between the transmitter and receiver, exceeding a guard interval, wherein the interference contribution is x k-1 h(n 1 ) where: x k-1 =(x k-1,−26 , x k-1,−25 , . . . , x k-1,25 , x k-1,26 ) and h ( n 1 )=( h ( n 1 ,−26), h ( n 1 ,−25), . . . , n ( n 1 ,−1), h ( n 1 ,1), . . . , h ( n 1 ,25), h ( n 1 ,26)) for −26 ≦n 1 ≦26 where h ⁡ ( n 1 , n 2 ) = ∑ k = 17 79 ⁢ f k ⁢ g ⁡ ( k - 16 , n 1 , n 2 ) ; determining a fast Fourier transform (FFT) output for the current OFDM symbol; and subtracting the interference contribution from the FFT output of the current OFDM symbol to form a modified FFT output.