New Approach to HF Channel Modeling and Simulation. Part 2. Stochastic Model

摘要

The report describes a new and unique approach for modeling either narrowband or wideband high frequency (HF) channels. Although narrowband models of the HF channel have existed for many years, they are applicable to only a limited set of actual narrowband propagation conditions. The need for an HF channel model that is valid for both narrow and wideband widths over a more extensive range of propagation conditions motivated the research documented in the report. The report describes the stochastic portion of the model which simulates the time-varying distortion of a transmitted signal due to dispersion, scattering due to irregularities in the ionosphere, Doppler spread and Doppler shift. The development of the stochastic model is described. The model output is compared with measured propagation data obtained on a variety of HF links. The mechanism for the comparison is the channel scattering function which has been found to be an excellent descriptor of the time-varying dispersive HF channel.