Synchronization methods for Bluetooth based WBANs

Abstract

Wireless Body Area Networks (WBANs) can take advantage of many wireless protocols. Among them, Bluetooth is a good candidate since its widespread adoption guarantees compatibility with a number of devices and significantly reduces development time. In most cases data collected from different sensors on different nodes need to be synchronized. We present a synchronization protocol that makes use of Bluetooth piconet internal clock to achieve near-millisecond accuracy with minimal radio communication overhead. Experimental results show that Bluetooth low power modes does not affect negatively accuracy, but improves it, obtaining less power consumption and higher synchronization accuracy.

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“…People are fashion-conscious, and hence, WBS must not only be non-invasive and comfortable, but also be elegantly designed with appealing aesthetics in such a way that performance is not hindered • Power Consumption: Affected by factors 2, 4-7; in order to optimize power consumption, the amount of energy expended by sensors for every bit of information could determine their performance [94]. Furthermore, as shown by [51] for Bluetooth-WBAN, synchronization strategies could help improve accuracy and limit unnecessary power consumption, thereby improving overall performance. Wake-up Radios (WURs) were proposed to listen to wireless channels in a power-efficient way through preamble sampling and continuous channel listening [145] • Network Efficiency: Affected by factors 2, 4, 5; optimal use of communication bandwidth is a key concern for nodes within WBAN, between WBAN nodes and sink or, in some cases, between sink and cloud.…”

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“…Bluetooth synchronization protocols based on the exchange of explicit synchronization messages suffer from highly variable messages latencies [26]; as a consequence, in our case, the shared network clock was used instead [27]. All Bluetooth devices are equipped with a 28-bit counter clock with 0.3125-ms resolution and a mandatory maximal drift of ±20 ppm.…”

“…The time synchronization problem for wireless networks has been extensively studied in the literature over the last two decades, and yet, there is no specific synchronization scheme capable of guaranteeing a high order of accuracy with great scalability, independent of the topology and application [ 25 ]. Bluetooth synchronization protocols based on the exchange of explicit synchronization messages suffer from highly variable messages latencies [ 26 ]; as a consequence, in our case, the shared network clock was used instead [ 27 ]. All Bluetooth devices are equipped with a 28-bit counter clock with 0.3125-ms resolution and a mandatory maximal drift of ±20 ppm.…”