Methods of packet-based synchronization in non-stationary network environments

摘要

Methods of packet-based synchronization in non-stationary network environments can include accumulating timestamps transmitted in packets between master and slave devices that are separated from each other by a packet network. Operations are also performed to determine whether first timestamps accumulated in a first direction across the packet network demonstrate that a first packet delay variation (PDV) sequence observed from the first timestamps is stationary. Thereafter, estimates of at least one of frequency skew and phase offset between the master and slave clocks are acquired using a first algorithm, from the first timestamps accumulated in the first direction. These operations of determining further include determining whether second timestamps accumulated in a second direction demonstrate that a second packet delay variation (PDV) sequence observed from the second timestamps is stationary.

主权项

1. A method of packet-based synchronization in non-stationary network environments, comprising:
accumulating timestamps transmitted in packets between master and slave devices, which are synchronized with respective master and slave clocks and separated from each other by a packet network; determining whether first timestamps accumulated in a first direction (master-to-slave) across the packet network demonstrate that a first packet delay variation (PDV) sequence observed from the first timestamps is stationary, using a first statistics-based stationarity-check algorithm for the first direction; and estimating at least one of frequency skew and phase offset between the master and slave clocks from the first timestamps accumulated in the first direction; wherein in the event the first packet delay variation (PDV) sequence observed from the first timestamps is not stationary, then said determining is followed by accumulating additional timestamps transmitted in packets between the master and slave devices and then determining whether second timestamps accumulated in a second direction (slave-to-master) demonstrate that a second packet delay variation (PDV) sequence observed from the second timestamps is stationary, using a second statistics-based stationarity-check algorithm for the second direction that is different from the first statistics-based stationarity-check algorithm.