Discussion and conclusions

The potential of multiple-input multiple-output orthogonal frequency division multiplexing (MIMO OFDM) as the basis for next-generation high data rate broadband wireless systems has been reported in many contributions over the last few years. A first reason is the high spectral efficiency, which is achieved by both techniques: OFDM places the subcarriers very close together and MIMO applies multiple spatial branches to transmit multiple parallel data streams. A second reason can be found in the possibility to operate MIMO OFDM systems in dispersive multipath environments. It is shown that these multiple-antenna OFDM systems even benefit from the dispersiveness of the multipath channel.

Many challenges, however, remain when regarding the efficient implementation of this kind of systems, due to their extremely high sensitivity to synchronisation errors and RF front-end imperfections. This book studies, and proposes tools to remove, several of the major hurdles on the path to successful application of these promising multiple-antenna and multicarrier techniques.