US 7,889,764 B2Granted

Method for the synchronization of data, such as distributed data, taking account of clock drifts and inaccuracies

AssigneesCentre National de la Recherche Scientifique (CNRS), Universite de Technologie de Compiegne (UTC)

InventorsPhilippe Bonnifait, Paul François Pierre Crubille, Véronique Cherfaoui, Hadji Amadou Gning El, Mohamed Shawky, Olivier Michel Bezet, Géry Brissot

Life of this patent

Estimating the term…

patentgrep

Loading patent…

Abstract

The present invention relates to a method for creating a correspondence between the local time of a first machine (B), having a first clock (HB), and that of a second machine (A), having a second clock (HA). The invention also relates to a method of synchronization between data recorded and date stamped by said first machine (B) with respect to the local time of said second machine (A). In order to make it more flexible and robust, this method does not comprise a synchronization of said clocks (HA, HB), but is based on the establishment of a correspondence ‘by intervals’ between the times that they indicate. In order to establish correspondence, a non-monotonic temporal reference may be formed by the clock of a synchronous bus connecting, at least temporarily, the two machines (and possibly other devices).

Claims15

Dependent claims

A method for establishing a correspondence by intervals ([TB], [TAB]) between the time (TB) indicated by a first monotonic clock (HB) and the time (TA) indicated by a second clock (HA), also monotonic, characterized in that it operates, over at least one temporal range (P1, P4), a first temporal reference (NT) common to the first and to the second clock and monotonic over said range, and in that said method comprises the steps of:

a) determining a first temporal interval ([TB1]) bounded by a first pair of time values (TB) of the first clock (HB) and belonging to a first temporal range (P1) over which the first temporal reference (NT) common to the first and to the second clock exists;
b) determining a second temporal interval ([TB2]) bounded by a second pair of time values (TB) of the first clock (HB) and belonging to a second temporal range (P4) over which the first temporal reference (NT) common to the first and to the second clock exists;
c) determining, by means of the common temporal reference (NT), a third temporal interval ([TAB1]), bounded by a first pair of time values (TA) of the second clock (HA), and containing the first temporal interval ([TB1]);
d) determining, by means of the common temporal reference (NT), a fourth temporal interval ([TAB2]), bounded by a second pair of time values (TA) of the second clock (HA), and containing the second temporal interval ([TB2]);
e) for any given fifth temporal interval ([TB]) bounded by a third pair of time values (TB) of the first clock (HB), calculating a sixth temporal interval ([TAB]), bounded by a third pair of time values (TA) of the second clock (HA), and containing said fifth temporal interval ([TB]), the calculation being performed by interpolation or extrapolation using said first ([TB1]), second ([TB2]), third ([TAB1]) and fourth ([TAB2]) intervals;
wherein at least the steps a) through e) are implemented by a computer.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/598,442Filed 17 Feb 2005
Priority: FR 04 021893 Mar 2004
Published: US 2007/0297457 A127 Dec 2007
Granted: 15 Feb 2011
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H04J 3/0661
Clock or time synchronisation among packet nodes: using timestamps
G06F 1/12
Generating or distributing clock signals or signals derived directly therefrom: synchronisation of different clock signals provided by a plurality…
G06F 1/14
Generating or distributing clock signals or signals derived directly therefrom: time supervision arrangements, e.g. real time clock
H04J
Multiplex communication