Abstract
This overview portrays the 40-year evolution of orthogonal frequency division multiplexing (OFDM) research. The amelioration of powerful multi carrier OFDM arrangements with multiple-input multiple-output (MIMO) systems has numerous benefits, which are detailed in this treatise. We continue by highlighting the limitations of conventional detection and channel estimation techniques designed for Multi-user MIMO OFDM systems in the so-called rank-deficient scenarios, where the number [3] of users supported or the number of transmit antennas employed exceeds the number of receiver antennas. This is often encountered in practice; unless we limit the number of users granted access in the base station’s or radio port’s coverage area. Following a historical perspective on the associated design problems and their state-of-the-art solutions, the second half of this treatise details a range of classic multi user detectors (MUDs) designed for MIMO-OFDM systems and characterizes their achievable pe