MIMO Wireless Channel Modeling and Experimental Characterization

While coding and signal processing are key elements to successful implementation of a MIMO system, the communication channel represents a major component that determines system performance. A considerable volume of work has been performed to characterize communication channels for general wireless applications. However, because MIMO systems operate at an unprecedented level of complexity to exploit the channel space-time resources, a new level of understanding of the channel space-time characteristics is required to assess the potential performance of practical multiantenna links. This chapter will focus on experimental measurements and models aimed at characterizing the MIMO channel spatio-temporal properties. Generally, we will define this channel to include the electromagnetic propagation, antennas, and transmit/receive radio circuitry, although different measurement and modeling techniques may include all or only part of this set. When evaluating the results of these modeling and measurement campaigns, much of the discussion will focus on the pertinent properties of the propagation environment. However, an examination of the topic of MIMO channels would be incomplete without some discussion of the impact of antenna element properties – such as directivity, polarization, and mutual coupling – antenna array configuration, and radio frequency (RF) architecture on communication behavior. Therefore, we will highlight techniques for including these channel aspects in MIMO system characterization and will