On the Design of Automatic Link Establishment in High Frequency Networks

Abstract

Most High Frequency (HF) communications systems deployed on the field today implement Automatic Link Establishment (ALE) techniques in order to help the HF stations automatically set up a link with good properties. Two generations (so called 2G and 3G ALE) have been standardized since the 90's, and are today being revisited due to the emergence of wideband HF waveforms. In this paper, we develop Markovian models of the 2G ALE procedure, which is nowadays the most widely used as it can operate while being completely asynchronous. Our models are "channel oriented", i.e., they observe the system from channel occupation perspective regardless of node status. We show by comparison with high-level OMNET++ simulations that our models provide fast and accurate estimation of all performance parameters of interest, and capture the main characteristics of the ALE process and the interactions between their numerous parameters. We believe that our work constitutes a useful tool to help operator plan and dimension HF networks. We also exploit the model to give some insight on the limitations of current 2G ALE, helping the design of future ALE strategies.