Simple and Low-Cost PLC Modem for IoT Applications

We present in this paper a simple and low-cost Power Line Communication (PLC) modem for Internet of Things (IoT) applications. The proposed modem implements a simple on-off-keying (OOK) modulation/demodulation with only discrete electronic components, not requiring complex ICs, such as processing units. It uses the ground and neutral wires as a channel communication, eliminating the need for complex isolation circuitry. To improve its robustness to noise, the developed PLC modem includes an automatic receiver gain adjustment and a transmitter sweep carrier frequency algorithm. Laboratory tests show that the developed PLC modem is capable of transmitting data at 9,600 bps with no errors if the noise spectral density in the power line is below 111 nVRMS2/Hz in the bandwidth of 150 kHz to 500 kHz. The system was also evaluated in a residential power network, where it presented a bit error rate below 1.21%. Due to its low cost, the developed PLC modem is suitable for low data rate IoT applications such as energy consumption monitoring, appliance monitoring and control, environmental monitoring (temperature, humidity, luminosity), security monitoring (presence sensors), etc.