CheepSync: A Time Synchronization Service for Resource Constrained Bluetooth LE Advertisers

Sridhar, Sabarish and Misra, Prasant and Gill, Gurinder Singh and Warrior, Jay (2016) CheepSync: A Time Synchronization Service for Resource Constrained Bluetooth LE Advertisers. In: IEEE COMMUNICATIONS MAGAZINE, 54 (1). pp. 136-143.

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Abstract

Clock synchronization is highly desirable in distributed systems, including many applications in the Internet of Things and Humans. It improves the efficiency, modularity, and scalability of the system, and optimizes use of event triggers. For IoTH, BLE - a subset of the recent Bluetooth v4.0 stack - provides a low-power and loosely coupled mechanism for sensor data collection with ubiquitous units (e.g., smartphones and tablets) carried by humans. This fundamental design paradigm of BLE is enabled by a range of broadcast advertising modes. While its operational benefits are numerous, the lack of a common time reference in the broadcast mode of BLE has been a fundamental limitation. This article presents and describes CheepSync, a time synchronization service for BLE advertisers, especially tailored for applications requiring high time precision on resource constrained BLE platforms. Designed on top of the existing Bluetooth v4.0 standard, the CheepSync framework utilizes low-level time-stamping and comprehensive error compensation mechanisms for overcoming uncertainties in message transmission, clock drift, and other system-specific constraints. CheepSync was implemented on custom designed nRF24Cheep beacon platforms (as broadcasters) and commercial off-the-shelf Android ported smartphones (as passive listeners). We demonstrate the efficacy of CheepSync by numerous empirical evaluations in a variety of experimental setups, and show that its average (single-hop) time synchronization accuracy is in the 10 mu s range.

Item Type:	Journal Article
Publication:	IEEE COMMUNICATIONS MAGAZINE
Publisher:	IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Additional Information:	Copy right for this article belongs to the IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	18 Feb 2016 05:29
Last Modified:	18 Feb 2016 05:29
URI:	http://eprints.iisc.ac.in/id/eprint/53281

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