Modeling of HF radio network in the Arctic region

Organizing reliable radio communication in the Arctic region is difficult due to specific climatic and geomagnetic conditions. The former complicates the installation and further operation of wired communication lines. The latter significantly affect the processes of long-distance propagation of HF radio waves using radio wave reflection from the polar ionosphere. Multiple signal relaying is designed to improve the quality of communication services by reducing the range of radio lines and decreasing the spatial scattering of radio waves. It is known [1] that the use of HF relays positioned in the southern direction is also one of the measures to improve the quality of radio communication in this region. However, the need for signal processing at the relay node requires time. Obviously, the increase in the overall speed of information exchange due to routing information flows along the highest-speed route can be lost with an unacceptably long signal processing time at the relay. Thus, the requirements for signal processing speed during relaying is a characteristic whose acceptable values should be determined. When designing a radio network and determining the requirements for relay equipment, it is necessary to consider at what delay time further use of relay nodes will not have a positive effect. To study the influence of delay at relay nodes on optimal routing in a shortwave radio network deployed in the Arctic region under various conditions. The article presents the results of a study on the influence of delays in signal relaying on optimal routing and the overall throughput of the HF radio network. The average data transmission rates were determined for three considered conditions: 12.57 kbps (in polar night conditions), 10.19 kbps (in polar day conditions), and 12.28 kbps (with uneven illumination of the route). A critical signal processing delay of 5 seconds at the relay was identified, above which the use of relaying becomes ineffective. It was found that in conditions of increased solar activity and polar day, the positive effect of relaying increases. It is shown that the effectiveness of using HF relays with omnidirectional antennas varies depending on radio wave propagation conditions. The obtained results can be used in designing an HF radio network in the Arctic region. The identified critical delay of 5 seconds is an important parameter when choosing equipment for relay nodes. Information about the most loaded nodes can be used in organizing radio communication infrastructure in the Arctic region, linking to existing settlements. The results of the study on the effectiveness of relays under various conditions will allow the development of adaptive routing algorithms that take into account the current state of the ionosphere.