Statistical modeling of low-latitude long-distance HF ionospheric multi-mode channels

Studies have been reported in the literature on High Frequency (HF) radio channels in mid-latitude areas more frequently than in low latitudes, where the ionospheric channels might behave differently. This paper reports a statistical model of HF sky wave channel complex impulse response and its parameters, i.e., channel gain, path gain, phase shift, and delay spread statistics, derived from both simulation and measurement on a 3044 km link in Indonesia. Evaluations show that multipaths observed with respect to their propagation delays form multiple clusters corresponding to different propagation modes. The channel gain is found to be Rayleigh distributed, whereas the rms and maximum delay spread exhibit Rayleigh and Gaussian distributions, respectively. This model can be used in performance evaluation of digital communication schemes in low-latitude HF channels.