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

A number of experimental and clinical studies have documented the risk potential of interference with implanted pacemakers by various types of cellular phones. Radiofrequency susceptibility of external medical equipment has also been reported in experimental studies. The purpose of this experimental study was to evaluate electromagnetic interference of external pacemakers by walkie-talkies and digital cellular telephones. External bipolar pacing was monitored using a digital oscilloscope to record pacemaker pulses and electromagnetic interference separately. Tests with the walkie-talkie, Private Mobile Radio (PMR) (160 MHz, 2.5 W) were conducted during the calling phase. Tests with the cellular phones, global system for mobile communications (GSM) (900 MHz, 2 W) and Digital Cellular System (DCS) (1,800 MHz, 1 W) were conducted in the test mode. Nine widely used external pacemakers from four manufacturers were tested. Various disturbances including pacing inhibition and asynchronous pacing were observed in eight pacemakers by the PMR, in four by the GSM phone, and in two by the DCS phone. The maximum distance that interference persisted ranged from 10-200 cm. This experimental study shows a potential risk of interference of external pacemakers by walkie-talkies and cellular digital phones. Appropriate warnings should be issued against the potentially serious risks of using communication devices in the vicinity of acutely ill patients treated with temporary transvenous cardiac pacemakers.

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IntroductionReverberation chambers have large popularity in the EMC area. Recently some applications have been reported for evaluating the performance of wireless antennas and communication systems. The multipath characteristics directly impact the performance factors. How much reverberation chambers constitute a realistic model of mobile wireless channel? This issue does not seem to have been properly addressed. The first order statistics of these chambers showing a Rayleigh distributed signals amplitude or equally chi-square distributed field strength have been largely investigated in the literature. The first order statistics are those for which time (or distance) is not a factor. The second order statistics of the fading indicate the information about the how the time is made up. This information is important for system engineering that requires the quantitative description of the rate at which fades of any depth occur and the average duration of fade below any given depth [1]. The required information is provided in terms of average fade duration (AFD) and level crossing rate (LCR). The manner in which these two terms are varying in the reverberation chamber is measured and compared to the theoretical values given for mobile wireless channels. Furthermore, the autocorrelation of the complex, inphase and quadrature components also the cross-correlation between the in-phase and quadrature components of the fading signals have been investigated. The field trial results are compared to the well known mathematical model of mobile channel simulator due to Clarke [2]. The best channel sounding rate for different test frequencies is found from the signals autocorrelation function. Measurements indicate that the number of uncorrelated signal samples in low frequencies is small. More uncorrelated samples are required to be able to compute the wireless antenna performances. This can be provided by gathering the signal samples in different locations in the chamber. The correlation coefficient between spatial points is measured specifies these locations.

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