Method and apparatus for time synchronisation in wireless networks
AssigneeImagination Technologies Limited
InventorIan R. Knowles
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Abstract
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.
Claims20
A wireless network, comprising:
- an access point comprising a first physical layer counter, wherein the access point is arranged to encode and transmit a timing synchronization frame over the wireless network, the timing synchronization frame comprising a timestamp derived from the first physical layer counter;
- and
- a wireless station comprising a second physical layer counter, a higher layer counter, and a clock interface coupled to the second physical layer counter and the higher layer counter,
- wherein the wireless station is arranged to receive the timing synchronization frame and decode the timestamp, control the second physical layer counter in dependence on the timestamp, and the clock interface is arranged to control the higher layer counter in dependence on the second physical layer counter.
A wireless station comprising:
- a physical layer comprising:
- a counter;
- and receiver and decoder circuitry for repeatedly receiving and decoding a timing synchronisation frame and a timestamp included therein, wherein the counter is controlled in dependence on the timestamp;
- and
- a clock interface connected to the counter and arranged to use the counter value to control a clock source for a higher layer function.
A wireless station comprising:
- a physical layer comprising:
- a counter;
- and receiver and decoder circuitry for repeatedly receiving and decoding a timing synchronisation frame and a timestamp included therein, wherein the counter is controlled in dependence on the timestamp;
- and
- a clock interface connected to the counter and arranged, responsive to receiving the timing synchronisation frame, to output a timing signal for use by a higher layer function.
Dependencies are inferred from the claim text.