Department of Electrical and Computer Engineering
M.S. Thesis Abstract
Connection Establishment in the Bluetooth System
Any communication between hosts in the Bluetooth system is preceded by a connection establishment procedure comprising two steps. The first step, referred to as Inquiry, enables hosts to learn about other hosts in their range. Inquiry can be omitted when not needed. The second step in which a host synchronizes and starts communication with the intended host is called Page. The complexity of the connection establishment procedure stems from the fact that hosts use different hopping sequences before a connection is established. The set-up delay is also affected by the requirement of low-power consumption and the possible connections that hosts may already have. The delay introduced by the procedure may impose constraints on applications such as ad hoc networking and LAN access.
We investigate the connection establishment when different paging modes are used. Analytical and simulation results show the range of values for the average page duration between two hosts. In a channel with packet errors, we derive analytical results for the average page duration as a function of the time interval a host allots to scanning for page messages. The most efficient connection establishment procedure takes up to 20 ms and comes at the expense of high power consumption since a host needs to scan for page messages continuously. In a second paging mode, a host wakes up to scan for page messages for a short time interval resulting in significantly higher delays. In such a situation, the average page duration shows a linear dependence on the time a host spends in pagescan in an error-free environment. In the presence of errors, such a behavior is observed only after the scan interval reaches a certain value depending on the channel error probability. For smaller values of the scan interval, the duration changes more rapidly.
Simulation results on the connection establishment procedure that consists of both inquiry and page illustrate the additional delay the inquiry procedure adds to the connection establishment.
Thesis Director: Professor Roy Yates