The project objective is to explore spectrum efficient wireless communications meeting the requirements of future aeronautical communications services at large, i.e., including Air Traffic Services (ATS), Airline Operational Communications (AOC), and Airline Passenger Communications (APC). This focus is motivated by the fact that by 2025, the air traffic in Europe is expected to be 2.4 times larger in volume than today (with important local variations). Diversity in types of airspace users (e.g., low-cost airlines, general and business aviation, and unmanned aerial vehicles) is expected to continue to grow1. The capacity of communication systems currently utilised for Air Traffic Management (ATM) is expected to saturate around 2015. Novel, spectrum-intensive passenger services must also be  included.

The main research goal is to analyze and design some key system components (to be detailed below) for use in promising transmission and networking schemes which can enable future spectrum-efficient aeronautical communications. Our investigations will be based on projections of future communication requirements and allocated frequency spectrum, and will include air-ground (a/g), air-air (a/a), as well as air-satellite (a/s) communication links. The research focus will thus be based on a proper characterization of the transmission media involved, and predictions of future traffic and service requirements. State-of-the-art technologies for spectrum efficiency enhancement will be employed and suitably modified and optimized. In particular, as specific research sub-goals we will design or propose:

• suitable space-time processing schemes using multiple antenna arrays,
• link adaptation and adaptive radio resource allocation schemes using adaptive coding, modulation, power control, and opportunistic access
• cooperative multi-hop relaying schemes and dynamical routing protocols with optimized power configurations
• advanced channel estimation and prediction techniques enabling reliable use of the above-mentioned technologies,

In general, a cross-layered design paradigm will be employed, within a multi-carrier (OFDM/OFDMA) framework. The interaction between terrestrial- and satellite-based parts of the overall communication network will be given particular attention, with special focus on assessing the added value that can be provided by properly including satellite  communications in an aeronautical framework.