By utilizing multi-antenna systems the dimension space can be used for encoding the information data. Due to the additional diversity it is possible to increase the error perfromance or the data rate.

Most concepts published so far, have been designed for non-frequency selective channels. In order to use these schemes in frequency-selective environments, appropirate equlization algorihtms have to be investigated. One choice is the equalization in frequency domain. Therefore, at the receiver side the signal is transformed into frequency domain by using the FFT and is equalized by multiplying with the inverse channel coefficients. After back transforming into time domain by using the IFFT the well known detection schemes for the mulit-antenna system can be applied.