Analysis of modulation methods for data communications over the low-voltage grid

The electric power supply network is a large infrastructure covering most parts of the inhabited areas. Due to the recent increase of demands in communication area, the electric power supply system is evolving from a pure energy distribution network to a multipurpose medium, delivering energy, voice and various data services (M. Zimmerman et al. (1999)). The technologies for data communications over the electrical power supply network are covered by the frequent term "power line communications" (PLC). The development of suitable PLC systems requires an analysis of communication properties that a powerline channel has to offer, such as the transfer function and the noise scenario. The channel characteristics have a direct influence on the choice of the appropriate modulation method, which transforms a data stream into a signal suitable for the transmission over a specific medium. The purpose of this paper is to analyze those mentioned topics. Simulations for various narrowband modulation schemes were made to present the final results in form of BER (bit error ratio) curves. The influence of the decision feedback equalizer (DFE) on suppression of inter symbol interference (ISI) was considered as well.