Channel occupancy — Faster, better, stronger

The new standard for narrowband PLC-based communications IEEE P1901.2 defines two mechanisms which do not exist in the majority of its wireless counterparts — dynamic frequency mapping (tone mapping), and existence of several modulations. Until now, the benefit of these mechanisms was not taken explicitly into account by the routing protocols. In this paper, we propose a novel metric for RPL — the Channel Occupancy (CO) metric. It accounts for the existence of multiple nominal throughputs over a given interface. The metric aims at minimizing the global channel occupancy time. In addition, we introduce a novel proactive link-estimation technique — COALE. This mechanism allows to fully benefit from the existence of multiple candidate parents under RPL. We evaluate the performance of a IEEE P1901.2-based Smart Meter network with RPL. We compare the performance gains of using Channel Occupancy instead of the widely popular expected transmission count (ETX). The results show that CO outperforms ETX by providing faster route formation times (up to 50%), lower end-to-end delays (up to 43%), lower signaling overhead (25%), and higher packet delivery rate (47%).