Adding accurate timestamping capability to wireless networks for smart grids

Smart grids rely on bi-directional communications between energy production sites and utilization sites. Usually, different approaches are used for implementing the required Wide, Field, and Home Area Networks (WAN, FAN and HAN, respectively). These networks are realized using very different (hybrid) technologies, for instance wired for WAN and wireless for FAN and HAN. However, an accurate common sense of time must be guaranteed among all smart grid participants, as it happens in any other distributed systems. Satisfying this need is challenging for wireless networks, while mature time distribution technologies are available for wired networks. The major issue for wireless devices is to provide accurate timestamping of network events, the key element of any time synchronization protocol. The objective of this paper is to propose low-cost and low-complexity timestamping techniques that also maintain full compatibility with already existing (unlicensed) communication standard for wireless nodes used in smart grids. In addition, a suitable platform exploiting the Software Defined Radio paradigm for comparative evaluation of these techniques is also discussed. Simulation and experimental results confirm the feasibility of the proposed approach, with the standard deviation of the timestamping error scalable down to 5 ns.