### Abstract

In a network of clocks, we consider a given reference node to determine the time evolution t. We introduce and analyze a stochastic model for clocks, in which the relative speedup of a clock, called the skew, is characterized by some given stochastic process. We study the problem of synchronizing clocks in a network, which amounts to estimating the instantaneous relative skews and relative offsets by exchange of time-stamped packets across the links of the network. We present a scheme for obtaining measurements in a communication link. We develop an algorithm for optimal filtering of measurements across a link (i, j) in order to estimate the logarithm of the relative speedup of node j with respect to node i, and we further study some implementation issues. We also present a scheme for pairwise offset estimation based on skew estimates. We study the properties of our algorithms and provide theoretical guarantees on their performance. We also develop an online centralized model-based asynchronous algorithm for optimal filtering of the time-stamps in the entire network, and an efficient distributed suboptimal scheme.

Original language | English (US) |
---|---|

Title of host publication | Proceedings of the 48th IEEE Conference on Decision and Control held jointly with 2009 28th Chinese Control Conference, CDC/CCC 2009 |

Pages | 5744-5749 |

Number of pages | 6 |

DOIs | |

State | Published - Dec 1 2009 |

Event | 48th IEEE Conference on Decision and Control held jointly with 2009 28th Chinese Control Conference, CDC/CCC 2009 - Shanghai, China Duration: Dec 15 2009 → Dec 18 2009 |

### Other

Other | 48th IEEE Conference on Decision and Control held jointly with 2009 28th Chinese Control Conference, CDC/CCC 2009 |
---|---|

Country | China |

City | Shanghai |

Period | 12/15/09 → 12/18/09 |

### Fingerprint

### Keywords

- Clock Offsets
- Clock Skews
- Clock Synchronization
- Distributed Systems
- Filtering and Estimation
- Network Delays
- Networked control
- Sensor Networks

### ASJC Scopus subject areas

- Control and Systems Engineering
- Modeling and Simulation
- Control and Optimization

### Cite this

*Proceedings of the 48th IEEE Conference on Decision and Control held jointly with 2009 28th Chinese Control Conference, CDC/CCC 2009*(pp. 5744-5749). [5399516] https://doi.org/10.1109/CDC.2009.5399516

**A model-based approach to clock synchronization.** / Freris, Nikolaos; Borkar, Vivek S.; Kumar, P. R.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

*Proceedings of the 48th IEEE Conference on Decision and Control held jointly with 2009 28th Chinese Control Conference, CDC/CCC 2009.*, 5399516, pp. 5744-5749, 48th IEEE Conference on Decision and Control held jointly with 2009 28th Chinese Control Conference, CDC/CCC 2009, Shanghai, China, 12/15/09. https://doi.org/10.1109/CDC.2009.5399516

}

TY - GEN

T1 - A model-based approach to clock synchronization

AU - Freris, Nikolaos

AU - Borkar, Vivek S.

AU - Kumar, P. R.

PY - 2009/12/1

Y1 - 2009/12/1

N2 - In a network of clocks, we consider a given reference node to determine the time evolution t. We introduce and analyze a stochastic model for clocks, in which the relative speedup of a clock, called the skew, is characterized by some given stochastic process. We study the problem of synchronizing clocks in a network, which amounts to estimating the instantaneous relative skews and relative offsets by exchange of time-stamped packets across the links of the network. We present a scheme for obtaining measurements in a communication link. We develop an algorithm for optimal filtering of measurements across a link (i, j) in order to estimate the logarithm of the relative speedup of node j with respect to node i, and we further study some implementation issues. We also present a scheme for pairwise offset estimation based on skew estimates. We study the properties of our algorithms and provide theoretical guarantees on their performance. We also develop an online centralized model-based asynchronous algorithm for optimal filtering of the time-stamps in the entire network, and an efficient distributed suboptimal scheme.

AB - In a network of clocks, we consider a given reference node to determine the time evolution t. We introduce and analyze a stochastic model for clocks, in which the relative speedup of a clock, called the skew, is characterized by some given stochastic process. We study the problem of synchronizing clocks in a network, which amounts to estimating the instantaneous relative skews and relative offsets by exchange of time-stamped packets across the links of the network. We present a scheme for obtaining measurements in a communication link. We develop an algorithm for optimal filtering of measurements across a link (i, j) in order to estimate the logarithm of the relative speedup of node j with respect to node i, and we further study some implementation issues. We also present a scheme for pairwise offset estimation based on skew estimates. We study the properties of our algorithms and provide theoretical guarantees on their performance. We also develop an online centralized model-based asynchronous algorithm for optimal filtering of the time-stamps in the entire network, and an efficient distributed suboptimal scheme.

KW - Clock Offsets

KW - Clock Skews

KW - Clock Synchronization

KW - Distributed Systems

KW - Filtering and Estimation

KW - Network Delays

KW - Networked control

KW - Sensor Networks

UR - http://www.scopus.com/inward/record.url?scp=77950815728&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=77950815728&partnerID=8YFLogxK

U2 - 10.1109/CDC.2009.5399516

DO - 10.1109/CDC.2009.5399516

M3 - Conference contribution

SN - 9781424438716

SP - 5744

EP - 5749

BT - Proceedings of the 48th IEEE Conference on Decision and Control held jointly with 2009 28th Chinese Control Conference, CDC/CCC 2009

ER -