An improved simulation of HF channel with Gaussian random time delays and doppler shifts

An improved high frequency (HF) channel model with random time-delays and random frequency shifts is proposed, on the basis of Watterson model. A software HF channel simulator is implemented using the proposed model. The frequency domain method is used to design the low-pass linear filter that generates the complex baseband tap-gain function with Gaussian spectrum density, representing the Doppler spread of HF channel. The time-delays and Doppler frequency shifts are both modeled as random variables with Gaussian distributed function. Simulation results prove the validity of the proposed HF channel simulator and provide some new insight into the time-varying properties of the HF channel. The proposed model can be used into the simulation of adaptive HF communication system and is much helpful to the design of hardware-based simulator.