ABSTRACT
Systems with multiple antennas (Figure 17.1) can exploit, besides the usual time and frequency, the spatial dimension, with large improvements in terms of diversity, interference mitigation and throughput. For this reason, they are among the key technologies in modern wireless transmission systems [1–7]. Even in wired systems (such as in digital subscriber line (DSL) and in power line communication (PLC) systems) since cables usually contain multiple wires, the channel can be seen as a multiple-input multiple-output (MIMO). In the following we will focus on MIMO wireless systems, but several of the described techniques can be applied also in wired systems.
