International audience

Power line communication is envisaged for the future more electric aircraft and the scenario studied in this work deals with the cabin lighting system, since its tree‐shaped architecture is sufficiently complicated to be representative of many other aircraft harness configurations. The statistical characteristics of the propagation channels are deduced from the measurements made on a representative test bench, the experimental values of the insertion gain being also compared with those obtained from a theoretical model based on the multiconductor transmission line theory. Field‐programmable gate array‐based modems have been designed and the performance of links are described and compared with predicted values deduced from a software tool simulating the link.

To limit the electromagnetic interference due to in-house PLC communication, standards on the emission levels of mains cables are now under elaboration. However, another additional aspect, not yet taken into account, deals with the possibility of exploiting the compromising radiated field to extract some information on the transmitted data. This problem of eavesdropping is known in the Electromagnetic Compatibility community, under the code name Tempest. The compromising propagation channel thus corresponds to the transmission by a modem between two wires of the power line and a reception on a loop antenna placed in adjacent rooms, apartments or houses. To evaluate this risk, a number of configurations are studied to determine the statistical properties of this channel. The influence of either the distance between the transmitting modem and the receiving loop, or of the walls between them, is investigated.

In this paper, we present a comprehensive study of the performance of a new model of DFT-precoded OFDMA with block-interleaved subcarrier allocation: B-IFDMA. The impact of the phase and timing jitter on the performance degradation for the two variants of B-IFDMA, namely joint-DFT and added-signal B-IFDMA is studied. Theoretical expressions of the degradation are derived for the additive white Gaussian noise channel and are compared with classical multicarrier schemes (OFDMA, MC-CDMA). Numerical results with various jitter parameters are presented and discussed. For the maximum number of active users, which is the critical case, it is shown that the phase jitter affects the two B-IFDMA variants and the classical multicarrier schemes in a similar fashion. Also, our results demonstrate that the two B-IFDMA variants are more sensitive to timing jitter than classical multicarrier schemes for a small number of blocks. Additionally, the number of blocks allocated to each user is found critical to minimize the degradation that occurs when timing jitter is introduced, and, therefore, must be carefully chosen.

The purpose of this paper is to examine the possibilities of increasing the channel capacity in tunnels, and particularly in railway tunnels, due to the use of multiple-input-multiple-output techniques. Many measurement campaigns have been carried out, considering the complicated geometric structure of these tunnels. We determine the channel characteristics by making a statistical analysis of correlation matrices between antennas and singular values of the channel transfer matrix. A comparison between the theoretical and experimental results is also presented. A stochastic channel model is then proposed and validated.