International audienceWe present in this survey new technologies proposed for the evolution of the aeronautical communication infrastructure. Motivated by studies that estimate the growth of air traffic flow, it was decided to develop a future communication infrastructure (FCI) adapted to the future aeronautical scenario. The FCI development involves researchers, industrials, and aeronautical authorities from many countries around the world, and started in 2004. The L-band Digital Aeronautical Communication System (L-DACS) is the part of the FCI that will be in charge of continental communication. The L-DACS is being developed in Europe since 2007 and two candidates were preselected: L-DACS1 and L-DACS2. In this paper, we first describe the motivations of the FCI. We then give an overview of its development activities from 2004 to 2009. After that, we provide some insights about both preselected L-DACS candidates, at their physical and medium access layers. Finally, we address the challenges on the development of the FCI/L-DACS

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a b s t r a c tThis paper investigates the situation where a group of terminals can be simultaneously connected to several base stations, using distinct technologies on non-overlapping frequency bands. We introduce and solve the problem of optimal power allocation (in the sense of the ergodic sum-rate), for terminals in the uplink, using three types of receiver: the optimum receiver, minimum mean square error and matched filters. Key results from random matrix theory allow us to solve the corresponding optimization problems. Simulations validate our approach, and illustrate the performance gain obtained by using several technologies simultaneously, instead of one at a time.

Abstract-Power Line Communication (PLC) systems are good candidates for next-generation aircraft communication channels. On-board power buses must meet stringent safety requirements that mandate the use of Transient Voltage suppressors (TVS) for lightning protection. These devices strongly degrade the performance of the communication channel. In this paper we analyze the impact of the lightning protection circuit used in aircraft power buses both theoretically and experimentally. It is shown that TVS devices are responsible for distortion and attenuation in the PLC signal band (1 MHz -100 MHz). We introduce a novel co-design strategy, matching PLC coupler to lightning protection conforming to air travel safety regulations. Our experimental results demonstrate that both constraints can be met using our proposed architecture.

Channel Division Multiple Access (ChDMA) is a promising multiple access scheme for Ultra-Wide Band (UWB) systems based on the use of the Channel Impulse Responses (CIR) as user signatures. In this work, we modeled the UWB-CIR as linear combinations of continuous impulses of finite duration randomly delayed. Two different channels are considered: the first, very simplistic, generates multipaths that are uniformly distributed over the time; the second model, which introduces correlation between the delay and the energy of the paths, is built based on the channel power profile. The capacity is investigated assuming no Channel State Information (CSI) at the transmitters and perfect CSI at the receiver. As results, we derive the asymptotic capacity of the ChDMA scheme when the number of users and the number of frequency dimensions (which is proportional to the bandwidth) go to infinity with constant ratio. As a consequence, we observe that the asymptotic spectral efficiency depends only on the system load, the power delay profile, the noise variance and the pulse signal. The results are validated in certain conditions and compared with known results on CDMA systems.

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