University of Twente Student Theses


Impact of multiple inquires on the bluetooth discovery process : and its application to localization

Franssens, Anne (2010) Impact of multiple inquires on the bluetooth discovery process : and its application to localization.

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Abstract:This thesis describes a research on the impact of multiple searching Bluetooth devices on the Bluetooth discovery protocol. Bluetooth is a standard which describes energy efficient wireless communication. Because of its characteristics, most mobile devices incorporate Blue- tooth as their means of wireless inter-device communication. In order for two devices to communicate using Bluetooth, they first need to set up a connection. A device can start a scan (inquiry scan) to discover available devices in the area. On a low level a device can be discovered without that device physically notifying its user. This principle is exploited to trace people as they move. This research focusses on the discovery time when using multiple inquirers (searching devices). This discovery time in uences the performance of a localization system. A series of experiments is set up to test this performance. A subset of these experiments are then used to create a model for modeling the discovery time for multiple inquirers. This model is based on the empirical data for one inquirer. At least twenty devices can be discovered by one inquiry scanner. All devices that are within range can be discovered in an average of 5 seconds if more than 1 inquirer is used. The dutycycle, which is the ratio of scanning versus backoff time of the inquirer, can be set to 6 and 7::8 periods. This ensures a minimal discovery time and low yet distributed backoff time. The number of inquirers that leads to the fastest discovery is 7, the maximum of the experiment. Because of collisions, a competition effect among inquirers exists. Modeling the discovery time and the number of inquirers leads to a model with acceptable accuracy.
Item Type:Essay (Master)
Faculty:EEMCS: Electrical Engineering, Mathematics and Computer Science
Subject:54 computer science
Programme:Internet Science and Technology MSc (60032)
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