New algorithm for IEEE 1588 time synchronization under the presence of significant delay variation

Abstract

Time synchronization is one of the basic services in a distributed network as it enables a lot of services, for example synchronized measurements or timeslot-based access to shared communication media. The IEEE 1588 defines the precision time protocol (PTP) that aims to synchronize multiple slave clocks to a master clock by means of synchronization event messages. Unfortunately, the accuracy of time synchronization strongly depends on delay variations produced by the underlying telecom network. Such behavior represents a strong issue, particularly considering the network consisting of devices that are not IEEE 1588 capable. A conventional clock servo will not provide enough accurate level of synchronization in the case of considerable delay variation. We develop a novel time synchronization algorithm that is based on a generic statistical approach and explicitly takes into account the stochastic properties of delay of PTP messages. Numerical simulations show that this algorithm is effective for estimation of the time offset between master and slave reliably, even under significant delay variations.