Interference characteristics of broadband power line communication systems using aerial medium voltage wires

The promise of broadband power line (BPL) communications - broadband access to virtually every home in the United States - remains unfulfilled if the radio emissions from these systems cause significant harmful interference to other users of the wireless spectrum. This article presents an elementary analysis of the physical mechanisms underlying these emissions, from which the interference characteristics of BPL systems can be derived. Numerical models are evaluated for idealized systems using overhead medium-voltage wires, a configuration that is of particular interest for U.S. deployments. The central conclusions of the analysis are: (i) BPL interference is governed primarily by two parameters: signal power and electrical balance of system excitation; (ii) interfering emissions are typically confined to the immediate vicinity of the BPL wire, but long-range effects cannot be neglected; and (iii) measurements on an installed BPL system suggest that it is operating within, but very close to, the limits set by rules recently adopted by the Federal Communications Commission.