A new approach for simulation of time varying HF channels

From the viewpoint of the system designer, HF simulators can provide a choice of channel characteristics and the possibility of modelling many different modem designs simultaneously. HF channel simulators are also used for comparative testing of HF modems, and provide standardised and repeatable test conditions, enabling a range of tests. The simplistic models which were suitable for low data rate modems can no longer provide the accuracy needed by HF system designers. This paper suggests a route to the goal of better modems, based on precision simulator technology which can incorporate the best physical and theoretical information concerning ionospheric behaviour as it becomes available