Improvement of L-DACS1 design by combining B-AMC with P34 and WiMAX technologies

All currently pursued air traffic management (ATM) concepts and associated roadmaps, i.e. Single European Sky ATM Research (SESAR) in Europe and next generation air transportation system (NextGen) in the USA, heavily rely upon trajectory exchange between airborne and ground automated systems. Facilitating such exchanges requires high performance air-ground (A/G) data link communications. The decision about what technology the future data link shall be based upon has not yet been taken, but it is obvious, that the selected data link technology must be globally accepted and standardized. L-band digital aeronautical communication system type 1 (L-DACS1) is one of the candidate air-ground data link technologies aiming at being deployed in the aeronautical L-band (960 - 1164 MHz). In the course of the action plan 17 (API7) activities the L-DACS1 system based on orthogonal frequency division multiplexing (OFDM) has been proposed to be further investigated and developed, together with another candidate technology, L-DACS2. The L-DACS1 specification has currently been developed under a EUROCONTROL contract by a team composed of FREQUENTIS, DLR, University of Salzburg and Selex communications. L-DACS1 strongly relies upon the broadband aeronautical multi-carrier communications (B- AMC) concept. One recommendation of the concluding API7 report was that the L-DACS1 design should combine that B-AMC technology with other "similar" OFDM-based technologies, primarily TIA-902 (P34) and IEEE 802.16e (WiMAX). This merging aims at further increasing the system performance and reducing implementation issues by relying on standardized technologies as far as possible. This challenging task has been recently conducted within the context of the L-DACS1 study by reviewing relevant standards and identifying items being potentially reusable within the L-DACS1 specification. This work was significantly facilitated via informal meetings and discussions with EUROCONTROL, FAA, NASA, ITT and MITRE. The authors highly appreciate the contributions of all involved parties to the consolidated work presented in this paper. The collaborative investigation of supplementary technologies revealed some highly interesting items related to the specification of airborne and ground L-DACS1 radio stations, as well as common items related to the physical layer and data link layer specification. As a consequence, the original B- AMC system design was supplemented and in some areas significantly improved by adopting specific P34 and WiMAX concepts from the related standards. This paper is based on the L-DACS1 specification as developed during the L-DACS1 study. A brief outline of the L-DACS1 design is given, highlighting the most important system features and modifications/improvements of the original B-AMC design. In the main part of the paper, the P34 and WiMAX concepts that have been considered and adopted during the L-DACS1 design phase are summarized and a rationale for their adoption is given. Additionally, explanations are provided for the P34 and WiMAX concepts that have been analyzed, but were rejected, and therefore not included in the L-DACS1 design.