System and method for correcting the clock drift and maintaining the synchronization of low quality clocks in wireless networks
AssigneeMeshNetworks, Inc.
InventorJohn M. Belcea
Life of this patent
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Abstract
A system and method for establishing and maintaining node clock synchronization in a wireless network. The system and method calculates the clock shift, clock drift and propagation delay values using a series of message exchanges and control algorithms between a selected reference node and a client node in a wireless network, then uses these values to synchronize the client node clock to the reference node clock.
Claims32
A method for controlling clock synchronization between at least two nodes of a plurality of nodes in an ad-hoc wireless network, comprising:
- controlling a client node of said plurality to select a reference node from said plurality and send to said reference node a first communication, said client node having a client clock and said reference node having a reference clock;
- controlling said reference node to receive said first communication and in response, send a first reply to said client node;
- controlling said client node to receive said first reply and in response, send a second and third communication to said reference node;
- and
- controlling said reference node to receive said second and third communications and in response, calculate a first clock shift and propagation value existing between said client node and reference node, and send said value to said client node in a second reply.
A method for controlling clock synchronization between at least two nodes of a plurality of nodes in an ad-hoc wireless network, comprising:
- controlling a clock synchronization message exchange between a client node and a reference node of said plurality of nodes;
- controlling said reference node to calculate a first clock shift and propagation value existing between said client node and reference node in response to said clock synchronization message exchange and provide said value to said client node;
- and
- controlling said client node to synchronize a client clock at said client node with a reference clock at said reference node using at least one of said value and a drift control algorithm.
A computer-readable medium of instructions for controlling clock synchronization between at least two nodes of a plurality of nodes in an ad-hoc wireless network, comprising:
- a first set of instructions, adapted to control a client node of said plurality to select a reference node from said plurality and send to said reference node a first communication, said client node having a client clock and said reference node having a reference clock;
- a second set of instructions, adapted to control said reference node to receive said first communication and in response, send a first reply to said client node;
- said first set of instructions further adapted to control said client node to receive said first reply and in response, send a second and third communication to said reference node;
- and
- said second set of instructions further adapted to control said reference node to receive said second and third communications and in response, calculate a first clock shift and propagation value existing between said client node and reference node, and send said value to said client node in a second reply.
Dependencies are inferred from the claim text.