  The market projection for Internet of Things (IoT) systems is appealing for
the Power Line Communication (PLC) technology. A massive growth and a pervasive
presence of these IoT objects is expected in our everyday life. About 20
billion of IoT devices are forecasted to be installed in the next two years.
PLC is a compelling technology that could become essential for certain IoT
applications. For example, sensor nodes and actuators used in the Smart
Buildings domain can be connected through PLC. In this case, the PLC network
will work as a backbone for the in-building communication. PLC systems, in this
domain, will help to solve or reduce the overcrowded-spectrum problem,
exploiting the existing cable infrastructure. Narrow band (NB) PLC is probably
the most suitable type of PLC technology for IoT applications. The main reasons
are: simple hardware, good coverage, appropriate bit-rate and low cost.
Nevertheless, to guarantee reliable connectivity further analysis and
improvements should be done. There are such as signal propagation
discontinuities, high channel attenuation and noise. Despite the fact that PLC
noise is a well-known problem, it still poses several challenges for this
technology. This paper aims at adding some new consideration on this topic.
This paper describes new results on MC NB noise. The MC noise is measured
between the Live-Protective Earth (L-PE) and between Neutral-Protective Earth
(N-PE) pairs (L-PE-N configuration), to exploit the symmetries of the channel.
The analysis in this paper considers the whole PLC NB frequency spectrum that
ranges from 3 kHz to 500 kHz. It considers the noise observed at the two output
ports of a given outlet in an in-building network with three conductors.
