Systems and methods for providing synchronization in a networked environment

摘要

Described herein are systems and methods for synchronization in a networked environment. For example, some embodiments provide methods for synchronizing a client device having a client media time reference with a server device having a server media time reference. In some cases such methods are embodied in computer readable code that is executable on one or more processors. Furthermore, some embodiments provide hardware, such as networked media devices that are configured to perform such methods. In overview, in some embodiments a client obtains timing information from a server and, on the basis of this timing information, applies an adjustment to a client control time reference, thereby to synchronize the client media time reference with the server media time reference. Some embodiments are particularly directed to the situation where there is a desire to synchronize networked media devices across a combination of wired and wireless networks.

主权项

1. A method, performed by a networked slave device, for synchronizing a local clock of the networked slave device with respect to a master clock of a master device, the method including:
(a) providing a group of probe frames to the master device, thereby to receive responses in respect of at least a selection of these probe frames, wherein each response includes data for allowing determination of an estimated clock offset, wherein the master device has access to observe a global clock value for a wireless network, and wherein the slave device and the master device are connected to different communication media; (b) filtering the responses, thereby to identify one or more best responses for the group of probe frames; (c) repeating steps (a) and (b) for successive groups of probe frames thereby to identify a respective one or more best responses for the successive groups of probe frames; (d) selectively calculating estimated clock offset values using the one or more best responses in respect of each group of probe frames to determine a relative clock offset drift based on:
(i) Return Trip Times (RTTs) for the one or more best responses with respect to their respective probe frames;(ii) a probe frame transmission timestamp taken with respect to the local clock of the networked slave device;(iii) a probe frame receiving timestamp taken with respect to the master clock of the master device;(iv) a response transmission timestamp taken with respect to the master clock of the master device; and(v) a response receiving timestamp taken with respect the local clock of the networked slave device; and (e) repeatedly adjusting the local clock of the networked slave device based on calculations of the relative clock offset drift.