Presentation title

Feedforward Temperature Compensation in High-Precision Clock Synchronization Schemes

Authors

Federico Terraneo, Zaigham Khalid, Alberto Leva and William Fornaciari

Institution(s)

Politecnico di Milano

Presentation type

Presentation of a research group from one or more scientific institutions

Abstract

Clock synchronization is a key functionality for the correct and efficient operation of distributed systems and real-time systems alike. It provides a shared common time for event ordering, as well as for task and communications scheduling. As a result, clock synchronization simplifies the design of software systems at various levels, from applications to system services (e.g: networking stacks). The range of systems that benefit from clock synchronization is significantly wide, spanning from huge data-centers to tiny embedded systems, and the widely different requirements and capabilities of said systems results in comparably different approaches to clock synchronization. In general, a clock synchronization scheme has to counteract two sources of uncertainty: those of the communication medium used, and those of the clock themselves. Our work focuses on the latter, and in detail, on the temperature dependence of quartz crystal oscillators which are commonly used for timekeeping. In this presentation, an extension of the FLOPSYNC-2 clock synchronization scheme is discussed, allowing the seamless integration of a feedforward clock correction coming from a temperature dependence model with the feedback clock correction of FLOPSYNC-2 achieved through message exchange. The presented extension is useful in scenarios where communication is expensive as it permits to increase the clock synchronization period for a given accuracy requirement compared to a feedback-only solution.

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Additional material

• Presentation slides: [pdf]