An assessment of a new ionospheric channel model driven by measurements of multipath and Doppler spread

HF propagation simulators have been used for many years to evaluate the performance of data modems. They allow testing to be carried out under repeatable, specified, propagation conditions and therefore allow performance comparisons to be made between different modems. Additionally, they allow simulation of a wide range of propagation conditions, whilst avoiding the expense of extended on-air trials. The bit error rates (BERs) for three modems have been generated with SUEDE (Simulation Using Extended Dispersion Envelope), a non-real-time HF channel simulation system, for a six hour simulation period. A comparison with existing Watterson (1970) model techniques for estimating modem availability has been presented, and a method of improving the Watterson model techniques has been suggested. Results from the new method show good agreement with the SUEDE simulation. The technique cannot provide estimates of BER in the same way as a full SUEDE simulation. However, this may not be required, especially for the serial tone modems, which break and recover very abruptly as the SNR difference changes sign