Compromising Electromagnetic Field Radiated by In-House PLC Lines

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.