Physical layer specification of the L-band Digital Aeronautical Communications System (L-DACS1)

L-DACS1 is the broadband candidate technology for the future L-band Digital Aeronautical Communications System (L-DACS). The flexible design of L-DACS1 allows the deployment as an inlay system in the spectral gaps between two adjacent channels used by the distance measuring equipment (DME) as well as the non-inlay deployment in unused parts of the L-band. In this paper, the specification of the L-DACS1 physical layer enabling the deployment as an inlay and as a non-inlay or as a mixed inlay and non-inlay system is presented. Apart from the transmitter design, the design of the L-DACS1 receiver is addressed including methods for mitigating interference from other L-band systems. Special emphasis is put on channel estimation which has to be robust towards interference. The different proposed algorithms for channel estimation are evaluated in simulations of the overall L-DACS1 physical layer performance. The results show that L-DACS1 is capable of operating even under severe interference conditions, hence confirming the feasibility of the inlay concept.