Powerline communication emissions and their influence on xdsl systems inside the home environment

Powerline communications (PLC) is a recent and rapidly evolving technology using the existing electricity power lines to provide telecommunication services. Although, since its first introduction on the low voltage electrical network to provide telecommunication services using low frequencies, PLC is today more commonly used for data transmissions at high rates (higher than 1 Mbit/s), also known as broadband powerline (BPL). As the power lines are not designed for high data rate transmissions, they will produce unintentional radio frequency emissions that may adversely cause high interferences in a wider frequency range than their own bandwidth (due to frequency harmonics and the statistical properties of noise like interference). Digital subscriber line (DSL) technology is currently used to deliver high data rates to users using the existing telephone lines. The lines of the two networks (the electricity power distribution and the telephone) are found close to each other in residential places and offices (sometimes in the same duct). A concern has been raised recently over the influence of using PLC technology on the delivery of services over the existing xDSL technologies, especially on the second generation of the very-high-speed digital subscriber line (VDSL2), where the two technologies overlap in the used frequency range. In this chapter, The PLC radiation is studied along with the interference between PLC and telephone lines inside the home environment including realistic measurements trying to envisage the influence of using PLC on the existing xDSL systems especially on the second generation vDSL (vDSL2).To cope with the interference problem and to guarantee a proper operation for the existing services, a solution based on filtering out the common-mode current is also presented.