Radioelectric compatibility of the future aeronautical communication system

The aeronautical community has recently decided to develop a new digital aeronautical communication system, named L-DACS, in order to fulfill the new air traffic requirements. This system, which will operate in the L frequency band (960 to 1164 MHz), would be internationally deployed from 2020. Many technologies were considered for this new aeronautical system but only two among them were preselected by the International Civil Aviation Organization (ICAO): candidate one, named L-DACS1, is based on a FDD-OFDM technology and candidate two, named L-DACS2, is based on a TDD-GMSK technology. One of the most important issues for both candidates is the electromagnetic compatibility (EMC) with the legacy systems operating in the same band or/and in adjacent bands. Different scenarios have to be evaluated due to the fact that these systems will be implanted either in the airplanes (on board) or in ground stations. In this paper, we propose to evaluate the air-air scenario, where we focus on the signals generated by onboard L-DACS transmitters on onboard victim receivers, taking into account the L-DACS antenna radiation pattern and the frequency mask. The study emphasizes that the interference phenomenon can be one of the main limitations for the L-DACS development.