Abstract
AbstractEvery year, the number of Internet of Things devices is growing exponentially. The current Internet of Things technology to support the connectivity of such a huge number of devices is limited by the coverage of the base stations deployed. In case of remote areas without coverage of any operator, the use of a satellite connection is such a high‐cost option. The only alternative option for very remote sensor is high frequency (HF) communications with ionospheric reflection. The HF band (3–30 MHz) with Near Vertical Incidence Skywave allows a large coverage area (up to 250 km) without the need of line of sight. The HF radio links usually need higher power transmissions with larger antennas supported by a mast. In this paper, we explore a new transmission scheme for low‐power transmissions, which is equivalent to use small and low gain HF antennas. We study the performance of several digital modulations using different bandwidths and transmission power. The field tests have been done around the Spanish Antarctic Base at Livingston Island to ensure the availability of the system even in polar areas where the behavior of the ionosphere is quite different from lower latitudes. However, the proposed physical layer fits well with any other remote location that requires low power data communication.
Highlights
Every year, the number of Internet of Things (IoT) connected devices is increasing constantly
We measured the real relationship between the bit error rate (BER) and bit energy to noise power spectral density (Eb/N0) of the received frames
Based on the results obtained, we can conclude that a 4QAM can be used with a transmission power of 2 W, since we will have a probability about 90% to have a BER lower than 0.004
Summary
The number of Internet of Things (IoT) connected devices is increasing constantly. In case of remote sensors, which are far (more than 10 km) from the nearest base station, the only alternatives without line of sight are satellites and high frequency (HF) communications. Other solutions such as repetition of the signal following the orography will solve the problem. In the case of an incidence angle between 70° and 90°, we refer to Near Vertical Incidence Skywave (NVIS) communications, with only one reflection achieving a radio coverage up to 250 km (see Figure 1), assuming 350 km as the maximum height of the ionosphere, (Witvliet & Alsina‐ Pagès, 2017).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
