2.7b Update: High Frequency Wave Forms for Difficult Conditions
Tracks
Track 2
| Wednesday, November 11, 2020 |
| 4:00 PM - 4:55 PM |
Speaker
Mr Arnstein Johansen
System Architect
Boeing Defence Australia
.
Abstract
High Frequency (HF) Band (2 – 30 MHz range) data communication has been used for many years and is the only medium that is “always there” for long-distance beyond-line-of-sight communications. The disadvantage is that HF communication paths using the ionosphere have some unique challenges. Therefore only low data rates have been achieved, and communication is not always successful. The ionosphere is in constant change, depending on solar activity, time of day and time of year. As a consequence, fading, Doppler spread, multi-path propagation, and interference, are a constant challenge.
This has led to a number of “smart” waveforms being developed to counter these variations. For example, the ADF’s DHFCS system provides many robust waveforms for data communications. Data rates are still slow, typically 75 – 2,400 b/s, and up to 9,600 b/s, but reliability is improved for when messages have to get through.
Recently improved and standardised waveforms being introduced can provide a more useful 9,600 – 64,000 b/s data rates (and beyond) over considerable distances.
Currently in development are newer techniques such as the use of Turbo codes and Gaussian Minimum Shift Keying. These are captured in proposed new standards.
From review of currently published research papers, proposed standards and other currently known research projects as well as discussions with vendors, it is clear that further improvements in performance are possible. Specifically, research can show that further improvements in waveform robustness can improve performance in difficult HF conditions, and over very long distances, using HF as the medium.
This has led to a number of “smart” waveforms being developed to counter these variations. For example, the ADF’s DHFCS system provides many robust waveforms for data communications. Data rates are still slow, typically 75 – 2,400 b/s, and up to 9,600 b/s, but reliability is improved for when messages have to get through.
Recently improved and standardised waveforms being introduced can provide a more useful 9,600 – 64,000 b/s data rates (and beyond) over considerable distances.
Currently in development are newer techniques such as the use of Turbo codes and Gaussian Minimum Shift Keying. These are captured in proposed new standards.
From review of currently published research papers, proposed standards and other currently known research projects as well as discussions with vendors, it is clear that further improvements in performance are possible. Specifically, research can show that further improvements in waveform robustness can improve performance in difficult HF conditions, and over very long distances, using HF as the medium.
Biography
Johansen, System Architect, Boeing Defence Australia is responsible for developing system architectural solutions on the Defence High Frequency Communication System (DHFCS).
Johansen joined Boeing in Brisbane more than 20 years ago to oversee all technical aspects of the ongoing development and upgrades of the original DHFCS. He is responsible for requirements definition and analysis, jointly with the Commonwealth of Australia and has published several papers relating to the DHFCS.
Prior to joining Boeing, Johansen was Chief Engineer at Racal Australia (now part of Thales), and Principal Engineer and Design Signatory at ADI (now also part of Thales) where he designed and integrated radios and communication systems.
Johansen was educated and graduated at the Norwegian Institute of Technology (now called the NTNU), Trondheim, Norway in 1978 as MSc in Electronics. He has worked as a design engineer in electronics and system design at NTNU since graduating.
Dr David Ingram
RF Communications Engineer
Boeing Defence Australia
.
Biography
Dr Ingram, RF Communications Engineer, Boeing Defence Australia, delivers RF engineering expertise in support of the business’ new campaigns and current programs. He joined Boeing Defence Australia in 2016 to work on a major enhancement program to the Defence High Frequency Communication System. Prior to joining Boeing, Dr Ingram worked in the electricity supply industry across the transmission, distribution, and generation sectors. Dr Ingram’s broad experience includes electronic products for monitoring and metering, development of smart grid applications, and assessment of real-time networking for automation applications. Dr Ingram holds Bachelor of Engineering (with First Class Honours) and Master of Engineering degrees in electrical and electronic engineering from the University of Canterbury (New Zealand), and a PhD from Queensland University of Technology. Dr Ingram has an Advanced amateur radio licence and is active in digital modes in the HF bands.
