A new power line modem and its performance in power line channels

• Main Author: Zhong, Tao
• Format: Others
• Language: English
• Published: 2009
• Online Access: http://hdl.handle.net/2429/4577

Intrabuilding electrical power supply lines provide readily accessible communication links. The Hot and Neutral lines in power line cable are used as the transmission channel in most power line communications scenarios. The Hot-Neutral is a hostile communication channel with high noise, high signal attenuation, changing impedance and signal fading. To avoid these difficulties, the Neutral-Ground channel is proposed and tested. Using Neutral-Ground channels in power line communication has advantages of lower attenuation, reduced impulse noise, higher input resistance, less signal fading, and more stable links. Neutral-Ground channels are viable as communication links when the transmitter-receiver separation is large enough to cause excessive signal attenuation for Hot-Neutral links and are recommended as the transmission channels in power line communications wherever possible. A power line modem was designed and developed. The modem was built around an untested prototype Binary Phase Shift Keying (BPSK) modulation and demodulation VLSI chip. The modem is supervised and controlled by a microcontroller. The firmware offers robust modem parameter control and data link control. The power line modem was tested on Hot-Neutral and Neutral-Ground channels. The modem BER is reasonably close to that determined assuming a white Gaussian noise channel. Using Neutral-Ground channels enables power line communications over wider distances with less transmitting power than when Hot-Neutral channels are used. Communications in Neutral- Ground are not affected by either the power line phases of the transmitter and receiver or by electric loads on power lines. Using an appropriate communications protocol, the modems successfully transferred large files from one computer to another via in-building poxyer line links. === Applied Science, Faculty of === Electrical and Computer Engineering, Department of === Graduate