On the Capacity of Narrowband PLC Channels

TL;DR

This paper models narrowband power line communication channels as linear periodically time-varying systems with cyclostationary noise, deriving their capacity and proposing a near-capacity transmission scheme that outperforms previous methods.

Contribution

It introduces a new capacity analysis for NB-PLC channels considering their periodic variations and noise, along with a practical coding scheme approaching this capacity.

Findings

Capacity is significantly higher with the optimal scheme.

The proposed scheme outperforms previous ad-hoc methods.

Periodic channel and noise properties are crucial for maximizing rate.

Abstract

Power line communications (PLC) is the central communications technology for the realization of smart power grids. As the designated band for smart grid communications is the narrowband (NB) power line channel, NB-PLC has been receiving substantial attention in recent years. Narrowband power line channels are characterized by cyclic short-term variations of the channel transfer function (CTF) and strong noise with periodic statistics. In this work, modeling the CTF as a linear periodically time-varying filter and the noise as an additive cyclostationary Gaussian process, we derive the capacity of discrete-time NB-PLC channels. As part of the capacity derivation, we characterize the capacity achieving transmission scheme, which leads to a practical code construction that approaches capacity. The capacity derived in this work is numerically evaluated for several NB-PLC channel configurations taken from previous works, and the results show that the optimal scheme achieves a substantial rate gain over a previously proposed ad-hoc scheme. This gain is due to optimally accounting for the periodic properties of the channel and the noise.