Evaluation of HF ALE linking protection

The resurgence of interest in high frequency (HF) radio may be largely attributed to the success of automation in making HF usable by operators with minimal HF training. Unfortunately, automatic link establishment (ALE) technology opens automated HF networks to possible hostile manipulation. To counter this vulnerability, a scheme called linking protection (LP) has been developed and standardized that scrambles ALE transmissions so that only legitimate users can interact with protected radios. The authors summarize the LP scheme, and present an evaluation of the impact of LP on linking performance. The evaluation includes both simulation results and measurements of early implementations.<>