Capacity Improvement Factor of HF Multi-Mode Skywave MIMO Channels

High Frequency (HF) communication systems as an emergency telecommunication technology can reach an isolated disaster region at large distances with the help of ionospheric reflections. In HF communication systems the utilization of multiple-input multiple-output (MIMO) antenna at both transmitter and receiver can increase the availability and channel capacity. This paper reports the 2×2 MIMO channel response measurement on a 3044 km link. The results are used to investigate the channel capacity improvement factor (CIF) over SISO channels when the MIMO configuration is used, which reveals that the CIF is in the range of 0.83-1.87. HF sky wave long distance communication systems with 2×2 MIMO configuration show an average capacity bigger than the average capacity of each SISO channel.