Compatibility Analysis Between Ldacs and Dme by Exploiting Gnu-Radio-Based Simulations and Laboratory Tests

The L-band digital aeronautical communication system (LDACS) is a forthcoming air-ground datalink that is poised to play an important role in the modernization of the Air Traffic Management (ATM) network. Operating within the frequency band of 960-1164 MHz, LDACS should not cause harmful effects on the legacy Distance Measuring Equipment (DME) system operating in the same band. This paper provides a quantitative assessment of the impact of LDACS interference on DME performance, specifically within a co-site scenario where LDACS reverse link (RL) transmissions from the airborne station interfere with the DME interrogator on the same aircraft. Compatibility evaluations between LDACS and DME are performed through simulations using GNU Radio, which yield the necessary Desired-to-Undesired signal power ratio (D/U) values for the successful synchronization of the DME system. Additionally, laboratory tests performed with a practical DME interrogator help determine the minimum D / U values essential for maintaining DME ranging performance. These combined efforts provide a reference for the ongoing development of the compatibility criteria that can ensure the effective coexistence of both systems in the aeronautical environment.