Queuing Analysis for Smart Grid Communications in Wireless Access Networks

The most challenging issue in Smart Grid (SG) communications is the management of a vast amount of SG traffic generated by large number of SG devices in the wireless access network. The wireless access network is leased by the electric utility from a telecommunications operator to connect power substations to numerous number of SG devices, such as phase monitoring units and smart meters. Thus, this access network, referred to as SG access network, carries both Human-to-Human (H2H) communications traffic and SG communications traffic. In this paper, we develop an analytical traffic model for a SG access network carrying H2H and SG traffic based on a priority queuing system. The SG traffic in the SG access network is classified as Fixed-Scheduling (FS) or Event-Driven (ED). The FS traffic is an operational traffic, which occurs on a periodic basis, such as smart meter readings. The ED traffic, which is assumed to have a higher priority, occurs as a response to electricity supply conditions, such as demand response. To date, we have not seen any traffic model for SG access networks, which considers the combination of periodic FS and random ED traffic in addition to H2H traffic. By using the proposed model, we derive expressions for the mean buffer length and mean queuing delay of each traffic. The derived expressions are validated by simulations of a wireless network model using real-world SG traffic profiles from the Ausgrid Smart Grid Smart City project and shown to agree well with the simulations.