Probabilistic Availability Quantification of PON and WiMAX Based FiWi Access Networks for Future Smart Grid Applications

Availability is one of the most important quality attributes for smart grid communications, as qualitatively defined in the IEEE P2030 standard. However, the availability metric must be quantified to validate given smart grid application requirements. In recent related work, availability has been quantified for wireless and optical backhaul networks in terms of communications reachability, while in some other work availability was not formally defined in a fine-grained manner and was assumed to be known. In this paper, we develop a novel multi-class probabilistic availability model for integrated passive optical network (PON) and WiMAX networks to quantify this metric according to medium access control (MAC) protocol limits as well as fiber and base station failures. The obtained numeric results show interesting availability behaviors, including the impact on availability depending on the number of base stations. We also investigate optical traffic re-routing through WiMAX when fiber faults occur and show that there exists a maximum amount of re-routed traffic for maximizing availability. Furthermore, we investigate a scenario of real-world smart grid traffic configurations shared with regular traffic and find the maximum sensor data rate to meet the availability requirements.