Analysis of transmission delay using communication protocol simulator in VHF datalink

VHF radio system has been used for Air Traffic Control (ATC) communication, Aircraft Operational Communication (AOC) etc. on the continental area. The data communication system of the VHF radio system uses communication protocols specified in the international standards called SARPs (Standards and Recommended Practices) of the ICAO (International Civil Aviation Organization). The VHF data communication system is commonly called the VHF datalink system. The VHF datalink system has been implemented into AOC, however it has not yet been implemented into ATC communication in Japan. By using the VHF datalink system, an air traffic controller can exchange requests or instructions with a pilot on a flying aircraft, and it significantly contributes to the safety of flight. CARATS, which is the abbreviation of “Collaborative Actions for Renovation of Air Traffic Systems”, is a long-term vision for the future air traffic systems of the Japan Civil Aviation Bureau (JCAB) [1]. JCAB challenges to change the current air traffic systems into more intelligent systems. We have been attending the activities of CARATS Working / Adhoc Group. We analyze the transmission delay as one of the performance analyses in the case of using the VHF datalink system for the part of the VHF ATC voice communication in the activities. For the analysis, we use the protocol simulator in which VHF communication protocol models are installed. In this paper, we first describe the background of performance analysis and the VHF datalink system simulator for aeronautical communication. Then, we show the results of statistical analysis to be used as some parameters for the simulator. Finally, we describe the results of simulations and predict the communication performance in the future.