Keynote II. Power line channels: frequency and time selective Part 1.-Response of indoor PLC channels

This Keynote discusses the behavior of indoor power line communications (PLC) channels when used for broadband transmission. The focus is put on the channel response characteristics and, particularly, on its time variant character. In order to create a model for a certain communication channel two strategies can be adopted. The first one is to define a structural model, based on the knowledge of the physical properties of the medium. In our case, they are: the power grid layout, the kind of wires installed, the devices connected to them and the points where transmitter and receiver are placed. From this point, a behavioral model can be derived, by calculating the transmission line parameters of the different sections of wire, the transmission matrices and, finally, the channel frequency response. That is a bottom-up approach, increasing the level of abstraction. The second one is to define directly a behavioral model, which is a simplified representation of the expected channel in a statistical sense. It should be based on some prior knowledge of the medium nature to adopt a clever mathematical model. Then, an extensive measurement campaign has to be carried out on different scenarios to adjust the statistical parameters of the model. That is to follow a top-down approach. The second kind of modeling is traditional in wireless channels. For instance, in GSM an impulse response with few echoes is assumed, and the statistical parameters are selected according to the scenario.