Clock drift compensation in a time synchronous channel hopping network

摘要

Disclosed are various embodiments for compensating for clock drift between nodes in a time synchronous network. A node receives time synchronization information from a parent node in the network. A drift between a clock of the node and a clock of the parent node is determined based upon the time synchronization information. The node identifies a number of time slots of the network since making a last time synchronization based on previous time synchronization information transmitted from the parent node. A compensation interval is calculated that represents a number of the time slots over which the clock of the node deviated, with respect to the parent node, by a predefined compensation value. The node compensates, by the compensation value, one of the time slots according to the compensation interval.

主权项

1. A method for clock drift compensation by a processor of a node in a network, comprising:
receiving time synchronization information from a parent node in the network; determining a drift between a clock of the node and a clock of the parent node based upon the time synchronization information; determining a number of time slots of the network that have elapsed since making a last time adjustment based on previous time synchronization information received from the parent node; calculating a number of clock ticks in the drift; calculating a number of elapsed time slots that resulted in one clock tick of drift by dividing the number of time slots by the number of clock ticks to obtain a compensation interval; using the compensation interval to compensate a selected time slot by one clock tick, wherein the selected time slot corresponds to one time slot within the compensation interval; and repeating said compensating using a same value for the compensation interval until a subsequent drift, based on subsequent time synchronization information, meets or exceeds a predefined drift threshold, wherein the subsequent drift meeting or exceeding the predefined drift threshold triggers calculating a new value for the compensation interval.