Project VDL2 – VDL Mode 2 Capacity and Performance Analysis

June 2014 – May 2015

The Objective of the study is to provide SESAR and the entire ATM community with a reliable picture concerning the VDL2 capability to support the evolution and the exploitation of DL services over the next years, when its limitations will be reached and what would be the consequences of reaching them, on the basis of the assumptions made.

Based on the simulation of the European air traffic up to 2040 (in 5 annual steps) the data communication of Air Traffic Services (ATS) and Aeronautical Operation Communications (AOC) at High Traffic Density and Medium Traffic Density will be determined. Based on in depth modelling of all the Air and Ground components, the simulation determined the VDL Mode 2 performance at the network level and also at each individual Ground Station level.

A cross-year analysis detailed, to provide an understanding of how the VDL Mode 2 datalink performances will decrease in comparison to increases of usage. Two areas of interest are deeply analysed, one representing the busiest airspace in Europe (including London, Paris and Brussels airports and centred on Lille) and an area with medium traffic (centered around Rome).
The topology model for this simulation reflects the existing geographical location of the Ground Stations (GS) in Europe. Although, the simulation does not consider the geographical redistribution of the stations, performance details per antenna are provided and the GS that are not performing well can clearly be identified for further investigation.

On the high density area, single frequency implementation is insufficient to service contemporary (2015) bandwidth demand. Progressive extension of VDL2 implementation to the four frequencies already allocated will alleviate the negative trend and postpone the bandwidth exhaustion horizon until 2025, or even later if a suitable network load balancing policy is implemented. On the medium density area, single frequency implementation will support service demand for another few years but not beyond 2020. Multi-frequency implementation, utilizing dedicated channels per traffic type (Airport, TMA/En-route) as well as dual squitter solution now pioneered by ENAV will postpone the sunset date to at least 2030, perhaps more if a suitable network load balancing policy is implemented.

• Link 2000+ DLS CRO Performance Monitoring Requirements, Eurocontrol / Network Manager
• Directorate, David Isaac, Ed. 1.3, 19 May 2014
• Requirements for monitoring through VDL Mode 2 channels edition, 0.4 – Eurocontrol
• Ad Hoc meeting on EUROCONTROL MF Roadmap, 2ndDecember 2013, EUROCONTROL Steven C. Bretmersky, Robert R. Murawski, and Vijay K. Konangi. “Characteristics and Capacity of VDL Mode 2, 3, and 4 Subnetworks”, Journal of Aerospace Computing, Information, and Communication, Vol. 2, No. 11 (2005), pp. 470-489.

ENAV (Project Manager of the consortium), University of Salzburg, ENAIRE, DFS, NATS, LFV supported by: DSNA, EasyJet, Air France, Lufthansa, SITA and Airbus.
The project partners expect such a study to represent a major enabler for clearing the future with the current uncertainties on which technological direction should be undertaken to secure the proper exploitation of the SESAR Future ATM Concept and by when, ultimately, significant R&D, standardisation, industrialisation and deployment activities should be displaced to overcome the risk of having, in the next future, the available air/ground communication infrastructure being a major impeding factor to the achievement of the expected improvements of the European ATM system toward the High Level Goals depicted by the European ATM Master Plan and, to a wider stack, by the ICAO Global Air Navigation Plan and the connected Aviation System Block Upgrades, by Horizon2020 and ultimately by the Flightpath 2050.

Contact: -Michele Carandente / ENAV -Carl-Herbert Rokitansky / University of Salzburg