Methods and systems for clock synchronization across wireless networks
First Claim
1. A method for synchronizing access points in a wireless local area network to enable a seamless transfer of a mobile device in the wireless local area network, communications in the wireless local area network being based on a plurality of timing patterns, the method comprising the steps of:
- designating as a top level in a hierarchy of piconets and a second piconet designed as a second level in the hierarchy, and wherein an initial access point has a master role for the first piconet, a second access point has a slave role in the first piconet, the second access point has a master role for the second piconet concurrently with having the slave role in the first piconet, and a third access point has a slave role in the second piconet, wherein the second access point has a first set of timing registers controlling a slave clock phase for the slave role in the first piconet, and a second set of timing registers controlling a master clock phase for the master role in the second piconet;
synchronizing the second access point having a second timing pattern of the plurality of timing patterns with the initial access point having an initial timing pattern of the plurality, the second access point adjusting the second timing pattern to match the initial timing pattern to produce a synchronized second timing pattern for use by the second access point;
synchronizing the third access point having a third timing pattern of the plurality of timing patterns with the second access point, by adjusting the third timing pattern to match the synchronized second timing pattern of the second access point to produce a synchronized third timing pattern for use by the third access point;
transferring a clock offset value from the first set of timing registers to the second set of timing registers to synchronize the slave role in the first piconet with the master role in the second piconet; and
transferring a connection for the mobile device by transferring an initial link between the mobile device and the initial access point to a transferred link between the mobile device and the third access point to provide for the seamless transfer of the mobile device as a function of synchronization of the initial access point with the third access point based on the initial timing pattern and the synchronized third timing pattern.
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Accused Products
Abstract
A wireless local access network includes a hierarchy of access points and mobile devices capable of roaming among the access points. Communications in the network is based on a time division approach, such as a Time Division Multiple Access (TDMA) approach, or spread-spectrum wireless communications approach. An access point that is intermediary in the hierarchy is a slave to a higher level master access point in the hierarchy. The intermediary access point is also master to one or more lower level access points. The intermediary access point synchronizes its clock with its master, and then provides the same synchronization (e.g., clock offset) to any lower level slaves of the intermediary access point so that the lower level slaves can synchronize with the intermediary access point. Thus, the lower level slaves share synchronization with the intermediary access point and the higher level master access point. A mobile device that is attached to one access point (such as the higher level master access point) is able to transfer to another access point (such as a lower level access point) without being required to resynchronize the mobile device'"'"'s clock.
154 Citations
25 Claims
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1. A method for synchronizing access points in a wireless local area network to enable a seamless transfer of a mobile device in the wireless local area network, communications in the wireless local area network being based on a plurality of timing patterns, the method comprising the steps of:
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designating as a top level in a hierarchy of piconets and a second piconet designed as a second level in the hierarchy, and wherein an initial access point has a master role for the first piconet, a second access point has a slave role in the first piconet, the second access point has a master role for the second piconet concurrently with having the slave role in the first piconet, and a third access point has a slave role in the second piconet, wherein the second access point has a first set of timing registers controlling a slave clock phase for the slave role in the first piconet, and a second set of timing registers controlling a master clock phase for the master role in the second piconet; synchronizing the second access point having a second timing pattern of the plurality of timing patterns with the initial access point having an initial timing pattern of the plurality, the second access point adjusting the second timing pattern to match the initial timing pattern to produce a synchronized second timing pattern for use by the second access point; synchronizing the third access point having a third timing pattern of the plurality of timing patterns with the second access point, by adjusting the third timing pattern to match the synchronized second timing pattern of the second access point to produce a synchronized third timing pattern for use by the third access point; transferring a clock offset value from the first set of timing registers to the second set of timing registers to synchronize the slave role in the first piconet with the master role in the second piconet; and transferring a connection for the mobile device by transferring an initial link between the mobile device and the initial access point to a transferred link between the mobile device and the third access point to provide for the seamless transfer of the mobile device as a function of synchronization of the initial access point with the third access point based on the initial timing pattern and the synchronized third timing pattern. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A gateway server for synchronizing access points in a wireless local area network to enable a seamless transfer of a mobile device in the wireless local area network, communications in the wireless local area network being based on a plurality of timing patterns, the gateway server comprising:
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a communication interface for communicating with an initial access point, a second access point, and a third access point;
the initial access point having an initial timing pattern of the plurality of timing patterns, the second access point having a second timing pattern of the plurality, and the third access point having a third timing pattern of the plurality, wherein the second access point has a first set of timing registers controlling a slave clock phase for the slave role in a first piconet, and a second set of timing registers controlling a master clock phase for the master role in a second piconet; anda digital processor coupled to the communication interface, the digital processor hosting and executing a gateway application that configures the digital processor to; designate the first piconet as a top level in a hierarchy of piconets and the second piconet designed as a second level in the hierarchy, and wherein the initial access point has a master role for the first piconet, the second access point has a slave role in the first piconet, the second access point has a master role for the second piconet concurrently with having the slave role in the first piconet, and the third access point has a slave role in the second piconet; direct the second access point to synchronize with the initial access point, the second access point adjusting the second timing pattern to match the initial timing pattern to produce a synchronized second timing pattern for use by the second access point; direct the third access point to synchronize with the second access point, the third access point adjusting the third timing pattern to match the synchronized second timing pattern of the second access point to produce a synchronized third timing pattern for use by the third access point; instruct the second access point to transfer a clock offset value from the first set of timing registers to the second set of timing registers to synchronize the slave role in the first piconet with the master role in the second piconet; and perform a connection transfer of an initial link between the mobile device and the initial access point to a transferred link between the mobile device and the third access point to provide for the seamless transfer of the mobile device as a function of synchronization of the initial access point with the third access point based on the initial timing pattern and the synchronized third timing pattern. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A system for synchronizing access points in a wireless local area network to enable a seamless transfer of a mobile device in the wireless local area network, communications in the wireless local area network being based on a plurality of timing patterns, the system comprising:
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a second access point in communication with an initial access point, the second access point for synchronizing the second access point with the initial access point, the initial access point having an initial timing pattern of the plurality of timing patterns, the second access point having a second timing pattern of the plurality and adjusting the second timing pattern to match the initial timing pattern to produce a synchronized second timing pattern for use by the second access point; a third access point in communication with the second access point, the third access point for synchronizing the third access point with the second access point, the third access point having a third timing pattern of the plurality of timing patterns and adjusting the third timing pattern to match the synchronized second timing pattern of the second access point to produce a synchronized third timing pattern for use by the third access point; wherein the wireless local area network includes a first piconet designated as a top level in a hierarchy of piconets and a second piconet designed as a second level in the hierarchy, and wherein the initial access point has a master role for the first piconet, the second access point has a slave role in the first piconet, the second access point has a master role for the second piconet concurrently with having the slave role in the first piconet, and the third access point has a slave role in the second piconet and the second access point has a first set of timing registers controlling a slave clock phase for the slave role in the first piconet. and a second set of timing registers controlling a master clock phase for the master role in the second piconet; and a gateway server in communication with the initial access point, the second access point, and the third access point, the gateway server for transferring a clock offset value from the first set of timing registers to the second set of timing registers to synchronize the slave role in the first piconet with the master role in the second piconet and performing a connection transfer of an initial link between the mobile device and the initial access point to a transferred link between the mobile device and the third access point to provide for the seamless transfer of the mobile device as a function of synchronization-of the initial access point with the third access point based on the initial timing pattern and the synchronized third timing pattern. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. A computer program product that includes a computer readable medium having computer program instructions stored thereon for synchronizing access points in a wireless local area network to enable a seamless transfer of a mobile device in the wireless local area network, communications in the wireless local area network being based on a plurality of timing pattern, such that the computer program instructions, when performed by a digital processor, cause the digital processor to:
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designate as a top level in a hierarchy of piconets and a second piconet designed as a second level in the hierarchy, and wherein an initial access point has a master role for the first piconet, a second access point has a slave role in the first piconet. the second access point has a master role for the second piconet concurrently with having the slave role in the first piconet, and a third access point has a slave role in the second piconet, wherein the second access point has a first set of timing registers controlling a slave clock phase for the slave role in the first piconet, and a second set of timing registers controlling a master clock phase for the master role in the second piconet; synchronize the second access point having a second timing pattern of the plurality of timing patterns with the initial access point having an initial timing pattern of the plurality, by adjusting the second timing pattern to match the initial timing pattern to produce a synchronized second timing pattern for use by the second access point; synchronize the third access point having a third timing pattern of the plurality of timing patterns with the second access point, by adjusting the third timing pattern to match the synchronized second timing pattern of the second access point to produce a synchronized third timing pattern for use by the third access point; transfer a clock offset value from the first set of timing registers to the second set of timing registers to synchronize the slave role in the first piconet with the master role in the second piconet; and transfer a connection for the mobile device by transferring an initial link between the mobile device and the initial access point to a transferred link between the mobile device and the third access point to provide for the seamless transfer of the mobile device as a function of synchronization of the initial access point with the third access point based on the initial timing pattern and the synchronized third timing pattern.
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23. A method for synchronizing access points in a wireless local area network to enable a seamless transfer of a mobile device in the wireless local area network, communications in the wireless local area network being based on a plurality of timing patterns, the method comprising the steps of:
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designating as a top level in a hierarchy of piconets and a second piconet designed as a second level in the hierarchy, and wherein an initial access point has a master role for the first piconet, a second access point has a slave role in the first piconet, the second access point has a master role for the second piconet concurrently with having the slave role in the first piconet, and a third access point has a slave role in the second piconet, wherein the timing patterns are based on time slots and wherein the second access point performs a plurality of further slave roles in the first piconet in a first set of time slots available to the second access point, and the second access point performs a plurality of further master roles for further piconets in a second set of time slots selected from time slots available to the second access point exclusive of the first set of time slots. synchronizing the second access point having a second timing pattern of the plurality of timing patterns with the initial access point having an initial timing pattern of the plurality, the second access point adjusting the second timing pattern to match the initial timing pattern to produce a synchronized second timing pattern for use by the second access point; synchronizing the third access point having a third timing pattern of the plurality of timing patterns with the second access point, by adjusting the third timing pattern to match the synchronized second timing pattern of the second access point to produce a synchronized third timing pattern for use by the third access point; and transferring a connection for the mobile device by transferring an initial link between the mobile device and the initial access point to a transferred link between the mobile device and the third access point to provide for the seamless transfer of the mobile device as a function of synchronization of the initial access point with the third access point based on the initial timing pattern and the synchronized third timing pattern.
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24. A gateway server for synchronizing access points in a wireless local area network to enable a seamless transfer of a mobile device in the wireless local area network, communications in the wireless local area network being based on a plurality of timing patterns, the gateway server comprising:
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a communication interface for communicating with an initial access point, a second access point, and a third access point;
the initial access point having an initial timing pattern of the plurality of timing patterns, the second access point having a second timing pattern of the plurality, and the third access point having a third timing pattern of the plurality; anda digital processor coupled to the communication interface, the digital processor hosting and executing a gateway application that configures the digital processor to; designate the first piconet as a top level in a hierarchy of piconets and the second piconet designed as a second level in the hierarchy, and wherein the initial access point has a master role for the first piconet, the second access point has a slave role in the first piconet, the second access point has a master role for the second piconet concurrently with having the slave role in the first piconet, and the third access point has a slave role in the second piconet wherein the timing patterns are based on time slots and wherein the gateway application configures the digital processor to instruct the second access point to perform a plurality of further slave roles in the first piconet in a first set of time slots available to the second access point; direct the second access point to synchronize with the initial access point, the second access point adjusting the second timing pattern to match the initial timing pattern to produce a synchronized second timing pattern for use by the second access point; direct the third access point to synchronize with the second access point, the third access point adjusting the third timing pattern to match the synchronized second timing pattern of the second access point to produce a synchronized third timing pattern for use by the third access point; instruct the second access point to perform a plurality of further master roles for further piconets in a second set of time slots selected from time slots available to the second access point exclusive of the first set of time slots; and perform a connection transfer of an initial link between the mobile device and the initial access point to a transferred link between the mobile device and the third access point to provide for the seamless transfer of the mobile device as a function of synchronization of the initial access point with the third access point based on the initial timing pattern and the synchronized third timing pattern.
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25. A system for synchronizing access points in a wireless local area network to enable a seamless transfer of a mobile device in the wireless local area network, communications in the wireless local area network being based on a plurality of timing patterns, the system comprising:
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a second access point in communication with an initial access point, the second access point for synchronizing the second access point with the initial access point, the initial access point having an initial timing pattern of the plurality of timing patterns, the second access point having a second timing pattern of the plurality and adjusting the second timing pattern to match the initial timing pattern to produce a synchronized second timing pattern for use by the second access point; a third access point in communication with the second access point, the third access point for synchronizing the third access point with the second access point, the third access point having a third timing pattern of the plurality of timing patterns and adjusting the third timing pattern to match the synchronized second timing pattern of the second access point to produce a synchronized third timing pattern for use by the third access point; wherein the wireless local area network includes a first piconet designated as a top level in a hierarchy of piconets and a second piconet designed as a second level in the hierarchy, and wherein the initial access point has a master role for the first piconet, the second access point has a slave role in the first piconet, the second access point has a master role for the second piconet concurrently with having the slave role in the first piconet, and the third access point has a slave role in the second piconet and the timing patterns are based on time slots; and a gateway server in communication with the initial access point, the second access point, and the third access point, the gateway server for; instructing the second access point to perform a plurality of further slave roles in the first piconet in a first set of time slots available to the second access point, and the second access point to perform a plurality of further master roles for further piconets in a second set of time slots selected from time slots available to the second access point exclusive of the first set of time slots; and performing a connection transfer of an initial link between the mobile device and the initial access point to a transferred link between the mobile device and the third access point to provide for the seamless transfer of the mobile device as a function of synchronization-of the initial access point with the third access point based on the initial timing pattern and the sycnchronized third timing pattern.
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Specification