Power Line Communication Over Flexible Cables for Elevator Cabins

Abstract

Narrowband power line communication has become a major focus of research with its applicability extending to residential facilities. This article examines data transmission over flexible AC power line cables stretching from the elevator control panel to the cabin. In previous studies, there has been no significant attempt to characterize the Power Line Communication (PLC) channel and noise of an elevator system. In this article, a vector network analyzer and mixed domain oscilloscope along with coupling devices are used to conduct power line channel noise and response measurements for an elevator system. The acquisition of channel transfer functions corresponding to both idle and moving states of the elevator is carried out for the 9 kHz–500 kHz frequency range. A mathematical model is provided for the average frequency response of the PLC channel. The main source of noise is the inverter that supplies power to the motor. The channel exhibits notable variations for frequencies less than 281 kHz while staying relatively consistent for the 281 kHz to 500 kHz frequency range as the elevator changes from idle to moving state. Reed Solomon and convolutional codes along with interleaving to spread erroneous bits are utilized in this work to simulate an orthogonal frequency division multiplexing transceiver. By systematically selecting subcarrier frequencies that do not overlap with the harmonic noise components, simulation results have demonstrated reliable data recovery for signal-to-noise ratio greater than 4 dB.