Impact of the Atmosphere on the Signal Phase and the Channel Capacity in EHF MIMO Satellite Links

Multiple-input multiple-output (MIMO) satellite systems are currently under intensive research due to their enormous potential to improve the link capacity. The key to achieve high multiplexing gains are the fine tuned phase relations inside the MIMO channel matrix. These relations are realized by a smart placement of the ground station antennas. However, the signal phase of a space- earth link is influenced by atmospheric distortions. Therefore measurements of the signal phase from related field campaigns are analyzed and examined regarding their relevance for the capacity prediction of real MIMO satellite links. Further, the impact of these phase distortions with respect to the resulting ergodic capacity and to the complementary cumulative distribution function of the channel capacity is investigated. Simulations point out only minor performance losses under the expectable conditions. Nevertheless, for a reliable forecast of MIMO satellite communication systems, additional measurements are needed.