Method and apparatus for time synchronisation in wireless networks

摘要

A wireless media distribution system is provided comprising an access point (6) for broadcasting media and a plurality of stations (2) for reception and playback of media. Each station is configured for receiving and decoding a timestamp in a beacon frame transmitted repeatedly from the access point. This is used to control the output signal of a station physical layer clock (12) which is then used as a clock source for an application layer time synchronisation protocol. This application layer time synchronisation protocol can then be used in the station to control an operating system clock (8) for regulating playback of media.

主权项

1. A wireless network, comprising:
a first wireless station comprising a first physical layer clock, a first software clock, and a first clock interface coupled to the first physical layer clock and to the first software clock; a second wireless station comprising a second physical layer clock, a second software clock, and a second clock interface coupled to the second physical layer clock and to the second software clock; and an access point having a third physical layer clock, wherein the access point is configured to encode and broadcast a beacon frame over the wireless network, the beacon frame comprising a timestamp derived from the third physical layer clock, wherein the first wireless station is configured to receive the beacon frame and decode the timestamp, to control the first physical layer clock in dependence on the timestamp, and the first clock interface is configured to control the first software clock in dependence on the first physical layer clock, and wherein the second wireless station is configured to receive the beacon frame and decode the timestamp, to control the second physical layer clock in dependence on the timestamp, and the second clock interface is configured to control the second software clock in dependence on the second physical layer clock, to synchronize the second software clock with the first software clock.