Study of the Capacity of Ricean MIMO Channels

It is well known that the use of antenna arrays at both sides of the communication link can result in high channel capacities provided that the propagation medium is rich scattering. In most previous works presented on MIMO wireless structures, Rayleigh fading conditions were considered. Here we study the capacity of MIMO systems under Ricean fading conditions. It is shown that MIMO Rayleigh channels exhibit a larger capacity than the equivalent Ricean channels for high signal-to-noise ratios (SNR) and large number of antennas. For small number of antennas, however, the inverse works, especially for low SNRs. On the other hand, it is shown that if the line-of-sight component is not very significant, the increase in the capacity of Ricean MIMO channels by increasing the number of antenna elements is still considerable. Flat (frequency non-selective) fading conditions are considered throughout the paper.