Capacity estimation of HF-MIMO systems

Multiple input multiple output (MIMO) systems utilize multiple antennas at both the transmitter and the receiver. This paper describes some recent experimental work that has been carried out in order to investigate the feasibility of applying MIMO techniques within the high frequency (HF) band. It is a significant development because the potential increase in data rates will benefit not only the existing HF radio systems but also open this band to new low cost communication applications. The capacity estimates for systems employing multiple antennas at the transmitter and receiver in the HF band are computed. Specifically a comparison is made between MIMO configurations employing homogenous antenna arrays and collocated antenna arrays in terms of their envelope correlation and capacity. The results indicate that the HF band can be used for MIMO applications and that compact collocated antennas can replace large homogenous arrays to provide potential capacity gains.