Methods and apparatus for synchronizing devices in a wireless data communication system
First Claim
1. A method implemented in a first wireless transceiver device of a wireless data communication system, the method comprising:
- receiving, from a second wireless transceiver device of the wireless data communication system, a first beacon that identifies (i) when the first wireless transceiver device is to listen for data and (ii) when the first wireless transceiver device is to send data, wherein the first beacon further includes a timestamp;
obtaining, from the first beacon, a time quality of a time source of the second wireless transceiver device, wherein the time quality of the time source of the second wireless transceiver device indicates how accurately the time source of the second wireless transceiver device reflects real time, the time quality of the time source of the second wireless transceiver device based at least in part on state characteristics of the second wireless transceiver device, the state characteristics of the second wireless transceiver device including;
whether the second wireless transceiver device has been asleep for at least a threshold amount of time;
whether the second wireless transceiver device has been in a low-power mode for at least a threshold amount of time;
whether the second wireless transceiver device is plugged in;
orwhether the second wireless transceiver device is operating on battery power;
determining a time quality of a time source of the first wireless transceiver device, wherein the time quality of the time source of the first wireless transceiver device indicates how accurately the time source of the first wireless transceiver device reflects real time;
adjusting, based on the timestamp in the first beacon, a clock of the first wireless transceiver device in response to the time source of the second wireless transceiver device reflecting real time more accurately than the time source of the first wireless transceiver device; and
leaving the clock of the first wireless transceiver device unadjusted in response to the time source of the first wireless transceiver device reflecting real time more accurately than the time source of the second wireless transceiver device.
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Abstract
The present disclosure describes methods and apparatus for synchronizing devices in a wireless data communication system. A wireless transceiver device of the wireless data communication system transmits a beacon at various intervals that includes both a timestamp indicating a current time and date of the transmitting wireless transceiver device, and a time quality indication indicating a quality of the time source of the transmitting wireless transceiver device. A wireless transceiver device receiving the beacon evaluates the time quality indication included in the beacon. If the time quality indication included in the beacon indicates the transmitting wireless transceiver device has a higher quality time source than the receiving wireless transceiver device, then the receiving wireless transceiver device adjusts its clock based on the timestamp in the beacon, otherwise the receiving wireless transceiver device need not adjust its clock based on the timestamp in the beacon.
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Citations
24 Claims
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1. A method implemented in a first wireless transceiver device of a wireless data communication system, the method comprising:
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receiving, from a second wireless transceiver device of the wireless data communication system, a first beacon that identifies (i) when the first wireless transceiver device is to listen for data and (ii) when the first wireless transceiver device is to send data, wherein the first beacon further includes a timestamp; obtaining, from the first beacon, a time quality of a time source of the second wireless transceiver device, wherein the time quality of the time source of the second wireless transceiver device indicates how accurately the time source of the second wireless transceiver device reflects real time, the time quality of the time source of the second wireless transceiver device based at least in part on state characteristics of the second wireless transceiver device, the state characteristics of the second wireless transceiver device including; whether the second wireless transceiver device has been asleep for at least a threshold amount of time; whether the second wireless transceiver device has been in a low-power mode for at least a threshold amount of time; whether the second wireless transceiver device is plugged in;
orwhether the second wireless transceiver device is operating on battery power; determining a time quality of a time source of the first wireless transceiver device, wherein the time quality of the time source of the first wireless transceiver device indicates how accurately the time source of the first wireless transceiver device reflects real time; adjusting, based on the timestamp in the first beacon, a clock of the first wireless transceiver device in response to the time source of the second wireless transceiver device reflecting real time more accurately than the time source of the first wireless transceiver device; and leaving the clock of the first wireless transceiver device unadjusted in response to the time source of the first wireless transceiver device reflecting real time more accurately than the time source of the second wireless transceiver device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A first wireless transceiver device of a wireless data communication system, the first wireless transceiver device comprising:
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a transceiver configured to receive, from a second wireless transceiver device of the wireless data communication system, a first beacon that identifies (i) when the first wireless transceiver device is to listen for data and (ii) when the first wireless transceiver device is to send data, wherein the first beacon further includes a timestamp; and a beacon based clock system configured to; obtain, from the first beacon, a time quality of a time source of the second wireless transceiver device, wherein the time quality of the time source of the second wireless transceiver device indicates how accurately the time source of the second wireless transceiver device reflects real time, the time quality of the time source of the second wireless transceiver device based at least in part on state characteristics of the second wireless transceiver device, the state characteristics of the second wireless transceiver device including; whether the second wireless transceiver device has been asleep for at least a threshold amount of time; whether the second wireless transceiver device has been in a low-power mode for at least a threshold amount of time; whether the second wireless transceiver device is plugged in;
orwhether the second wireless transceiver device is operating on battery power; determine a time quality of a time source of the first wireless transceiver device, wherein the time quality of the time source of the first wireless transceiver device indicates how accurately the time source of the first wireless transceiver device reflects real time; adjust, based on the timestamp in the first beacon, a clock of the first wireless transceiver device in response to the time source of the second wireless transceiver device reflecting real time more accurately than the time source of the first wireless transceiver device; and leave the clock of the first wireless transceiver device unadjusted in response to the time source of the first wireless transceiver device reflecting real time more accurately than the time source of the second wireless transceiver device. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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21. A non-transitory computer-readable memory device comprising computer-executable instructions that, when executed, implement a system in a first wireless transceiver device of an wireless data communication system to:
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receive, from a second wireless transceiver device of the wireless data communication system, a first beacon that identifies (i) when the first wireless transceiver device is to listen for data and (ii) when the first wireless transceiver device is to send data, wherein the first beacon further includes a timestamp; obtain, from the first beacon, a time quality of a time source of the second wireless transceiver device, wherein the time quality of the time source of the second wireless transceiver device indicates how accurately the time source of the second wireless transceiver device reflects real time, the time quality of the time source of the second wireless transceiver device based at least in part on state characteristics of the second wireless transceiver device, the state characteristics of the second wireless transceiver device including; whether the second wireless transceiver device has been asleep for at least a threshold amount of time; whether the second wireless transceiver device has been in a low-power mode for at least a threshold amount of time; whether the second wireless transceiver device is plugged in;
orwhether the second wireless transceiver device is operating on battery power; determine a time quality of a time source of the first wireless transceiver device, wherein the time quality of the time source of the first wireless transceiver device indicates how accurately the time source of the first wireless transceiver device reflects real time; adjust, based on the timestamp in the first beacon, a clock of the first wireless transceiver device in response to the time source of the second wireless transceiver device reflecting real time more accurately than the time source of the first wireless transceiver device; and leave the clock of the first wireless transceiver device unadjusted in response to the time source of the first wireless transceiver device reflecting real time more accurately than the time source of the second wireless transceiver device. - View Dependent Claims (22, 23, 24)
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Specification