1. A method of frequency domain equalization in communication systems, the method comprising: receiving a transmit signal over a channel; generating a vector by sampling and converting the transmit signal to a frequency domain signal; generating an equalized vector by multiplying an equalization matrix to the sampled vector; generating an estimate of data vector by inverse converting the equalized vector; and recovering data included in the transmit signal based on the estimate of data vector, wherein the equalization matrix {circumflex over (Ω)} is generated based on a frequency domain correlation matrix {circumflex over (R)} of CCI (co-channel interference) plus noise, wherein the equalization matrix {circumflex over (Ω)} is an MN×MN matrix defined as {circumflex over (Ω)} {circumflex over (R)}⊙(1 M×M {circle around (x)}I N ), where the integer M>1, the integer N>1, 1 M×M is an M×M all-one matrix, and I N is an N×N diagonal matrix.