Joint node localization and time-varying clock synchronization in wireless sensor networks

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

The problems of node localization and clock synchronization in wireless sensor networks are naturally tied from a statistical signal processing perspective. In this work, we consider the joint estimation of an unknown node's location and clock parameters by incorporating the effect of imperfections in node oscillators, which render a time varying nature to the clock parameters. The data exchange mechanism is based on a two-way message exchange with anchor nodes. In order to alleviate the computational complexity associated with the optimal maximum a-posteriori estimator, two iterative approaches are proposed as simpler alternatives. The first approach utilizes an Expectation-Maximization (EM) based algorithm which iteratively estimates the clock parameters and the location of the unknown node. The EM algorithm is further simplified by a non-linear processing of the data to obtain a closed form solution of the location estimation problem using least squares (LS). The performance of the estimation algorithms is benchmarked by deriving the Hybrid Cramer-Rao lower bound (HCRB) on the mean square error (MSE) of the estimators. The theoretical findings are corroborated by simulation studies which reveal that the LS estimator closely matches the performance of the EM algorithm for small time of arrival measurement noise, and is well suited for implementation in low cost sensor networks.

Original languageEnglish
Article number6596074
Pages (from-to)5322-5333
Number of pages12
JournalIEEE Transactions on Wireless Communications
Volume12
Issue number10
DOIs
Publication statusPublished - Oct 2013

Fingerprint

Clock Synchronization
Wireless Sensor Networks
Clocks
Wireless sensor networks
Time-varying
Synchronization
Vertex of a graph
Expectation-maximization Algorithm
Electronic data interchange
Location Estimation
Estimator
Cramer-Rao Lower Bound
Unknown
Anchors
Time of Arrival
Mean square error
Expectation Maximization
Maximum a Posteriori
Sensor networks
Data Exchange

Keywords

  • Clock synchronization
  • EM algorithm
  • least squares
  • node localization
  • wireless sensor networks

ASJC Scopus subject areas

  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

Cite this

Joint node localization and time-varying clock synchronization in wireless sensor networks. / Ahmad, Aitzaz; Serpedin, Erchin; Nounou, Hazem; Nounou, Mohamed.

In: IEEE Transactions on Wireless Communications, Vol. 12, No. 10, 6596074, 10.2013, p. 5322-5333.

Research output: Contribution to journalArticle

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