Adaptive HF radio test results using real-time channel evaluation systems

To facilitate the development of anti-interference features for proposed Federal Standard 1049 (adaptive high-frequency (HF) radio standard), adaptive radio systems and concepts have been solicited from Government and industry. One such contribution is an adaptive HF radio system, termed the SMARTNET (Skywave Management for Automatic Robust Transmission Network), that is capable of adapting power, data rate, and frequency under the direction of a network control computer. A recent over-the-air test was conducted to characterize system behavior on an 1100 kM test link between Boulder, CO, and Richardson, TX. A second adaptive system, capable of adapting frequency and based upon the Federal Standard 1045 Automatic Link Establishment (ALE) protocols, operated in parallel with the SMARTNET system during the test period. Data was collected automatically from both systems and analyzed off-line so that the results were compared with predicted data generated by the Ionospheric Communication Enhanced Profile Analysis Circuit Prediction Program (ICEPAC). ICEPAC is an improvement on the older Ionospheric Communications Analysis and Prediction Program (IONCAP). Comparison of the two systems consisted of: (1) power required to maintain the link, (2) selection of the best frequency, and (3) link availability percentage. This paper presents these results, and where appropriate, attempts to draw conclusions as to the significance of future adaptive HF data networks, and to the emerging Federal Standard 1049 interoperability standard