Radio Propagation Prediction for HF Communications

Abstract

The refraction and apparent reflection of HF radio waves by the ionosphere enables long range HF radio communications. The ionosphere is a distinctly irregular medium that is mostly driven by solar activity. Ionospheric models are useful in the prediction of ionospheric behaviour and in the provision of data required for the analysis and forecasting of ionospheric propagation. This paper provides a compact review of HF radio propagation prediction techniques and approaches for HF communications. The paper also highlights the numerous approaches have been used to date in an attempt to estimate F2 usable frequencies. The review presented in this paper is inspired by the most recent advances in the field of ionospheric prediction and modelling.

Determination of the Annual Optimal Reliable Frequency for Different Transmitter/Receiver Stations Distributed over the Iraqi Territory

“…The frequency from the specified set with the maximum signal to noise ratio (S/N), which also satisfies the specified minimum take-off angle, the required S/N ratio, and the probability level. The BUF graph for each hour is selected by the frequency set user and determined on the basis of ionospheric conditions and the user-specified system details [10].…”

Comparison of Prediction Programs for Short Wave Circuit Link from Iraq to Test points on Both Earth Hemispheres during Solar Minimum

“…If the Solar Flux Index (SFI) increases, the layer's ionization will increase , causing the critical frequencies for these layers to increase too which makes higher frequencies transmitted diffract back to earth again [1]. According to eq (1) as the transmitted frequency increases, the more time it takes to fly in the ionosphere layers before getting refracted back to earth and hence ground distance increases [2,3]. To make a radio contact successfully on HF between two points, if a frequency is greater than the Maximum Usable Frequency ( MUF), the signal will penetrate the ionosphere and escape to space and never come back to earth again ,so the working frequency must be less than the MUF and is called the Frequency of Transmission (FOT) [4].…”

“…The A parameter is a linear variable that represents the magnetic field of the earth. The previous papers [1][2][3][4][5][6][7][8][9][10] focused on the comparison of prediction programs at different geomagnetic circuits and different solar activity without mention to the Iraqi HF circuit link, while [11,12] studied the ionospheric parameters for Iraq's zone only when solar winds were at their maximum. The novelty of this work is studying and comparing the propagation prediction for the HF circuit link from Iraq to the world at the solar wind's minimum using the Voice of America Coverage Analysis Program (VOACAP), ITU Recommendation RS 533 (REC533), and real radio contact during August 2018; and also to find which modulation is preferred digital mode like FT8 [13] or analogue.…”

Field strength prediction based on deep learning under small sample data

“…Introduction: Radio wave propagation prediction possesses significant implications for wireless network planning and optimization [1]. The propagation process of radio waves is extremely complex and is influenced by numerous external factors, such as terrain, weather and environmental characteristics [2].…”

“…Furthermore, NN1 is replaced with an untrained three-layer FCN(named the NN3), and the NN2 structure remains unchanged Table 2. The relevant parameters of the previous model Channels [100, 50, 20, 3] Kernel size [(5,5), (3,3), (3,3), (2,2)] Max pooling [2, 2, 2, 2] NN3 layer size [64, 64, 3]NN2 layer size[16,1]…”