Patent ID: 8489776
Filing Date: 2013-07-16
Classification: H04J,H04L,H04W

Abstract:
1. A method for synchronizing devices from a central access point node in which synchronization messages may be lost, the method comprising steps of: utilizing a low latency protocol from the central access point node to the devices to transmit a first series of synchronization messages, each synchronization message in the first series including a central access point node timestamp; transmitting a second series of synchronization messages from the devices to the central access point node in response to the first series of synchronization messages, wherein the second series is smaller than the first series due to lost messages and each synchronization message of the second series includes a corresponding device timestamp respective to each device, wherein the device timestamp derives from a clock of each device calculating an intermediate average clock offset for each device, the intermediate average clock offset being equal to a difference between the central point node timestamp and the device timestamp for each synchronization message of the second series; calculating an overall relative clock offset equal to an average of the intermediate average clock offsets for each device; synchronizing the clock of each device by applying the overall relative clock offset for each device; transmitting data acquisition commands from the central access point node to the devices using a high reliability protocol different from the low latency protocol; and receiving responses to the data acquisition commands at the central access point node from the devices.