UBC Theses and Dissertations
A new two-phase scatternet formation algorithm for bluetooth wireless personal area networks Zhang, Chu
A Bluetooth multi-hop personal area network can be formed by interconnecting one or more piconets into a scatternet. A Bluetooth scatternet is an ad hoc network in which the devices move randomly and organize themselves. The scatternet is attractive because it can extend the Bluetooth radio range and improve the network capacity. The current Bluetooth specification  only defines the scatternet but does not address how the scatternet is formed. To reduce the high load on the master nodes and bridge nodes, a twophase scatternet formation (TPSF)  algorithm has been proposed in which a control scatternet is created for the control traffic in the first phase and an on-demand scatternet is created for the data traffic in the second phase. In TPSF, route information for the ondemand scatternet on each node is discovered only when the node initially accesses the network. The original TPSF does not consider the support of mobility. In this thesis, we propose a new scheme which is called TPSF+ for the on-demand scatternet formation in the second phase of TPSF. In TPSF+, route information is discovered when a communication session is required between the two nodes. Consequently, the on-demand scatternet can be formed with much higher success ratio when the slaves randomly move around the master after accessing the network. We also propose to use PM_ADDR (Parked Member Address) instead of BD_ADDR (Bluetooth Device Address) during route discovery in order to reduce the time of the route discovery process. Furthermore, to reduce the hop distance of the on-demand scatternet, we limit the number of hops in each piconet in the control scatternet. Based on the simulation results, we show that our scheme can improve network performance greatly in terms of aggregate throughput and end-to-end delay even with the consideration of packet collisions. With the slaves randomly moving around the master, TPSF+ achieves much better performance in terms of a higher successful path connection ratio.
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