Massive multi-user MIMO with DFT spreading for antenna mutual coupling and interference

A massive MIMO technique uses more than 100 antennas. According to several recent results, it can increase 10 times or more channel capacity than a conventional MIMO system with small number of antennas. However, one critical problem of this system is that it should overcome channel correlations such as spatial correlation and antenna mutual coupling. In order to overcome these problems, a new massive multi-user MIMO (MU-MIMO) with Discrete Fourier Transform (DFT) spreading is proposed. The proposed scheme includes additional DFT/IDFT block and distributes symbols into large size MIMO antennas. When some antennas of a massive MIMO are mutually coupled or interferences occur, the corrupted symbols are distributed in different domain by DFT spreading. It is shown with simulation that the proposed scheme obtains significant performance improvement under the given simulation configuration.