A New Approach to the Modeling of the Transfer Function of the Power Line Channel

Abstract – The “indoor” access network is characterized by several branches and impedance mismatches that cause many reflections. In the present paper, a new way of modeling the transfer function of a power line is proposed. The proposed model starts by considering the power line channel as a uniform transmission line. This allows the power line channel to be described as a cascade of simple two-port networks, each of which may be easily described with its transmission matrix. This approach allows us to model in the frequency domain any power line channel, regardless of its topology, by considering as special two-port networks any series or shunt impedances (i.e., branches) present along the line. This approach also implies the validity of the TEM approximation. It is possible to prove that this assumption is valid assuming correct mode excitation, which differs from conventional twisted pair. In so doing, the usual problems encountered in the time-domain characterization of the power line channel as a multipath channel can be avoided. Interestingly, the transmission matrices approach allows us also to show the existence of a particular symmetry of the power line channel that was not previously revealed [5].