a pseudo random coordinated scheduling algorithm for bluetooth scatternets
The emergence of Bluetooth as a default radio interface allows handheld devices to be rapidly interconnected into ad hoc networks. Bluetooth allows large numbers of piconets to form a scatternet using designated nodes that participate in multiple piconets. A unit that participates in multiple piconets can serve as a bridge and forwards traffic between neighbouring piconets. Since a Bluetooth unit can transmit or receive in only one piconet at a time, a bridging unit has to share its time among the different piconets. To schedule communication with bridging nodes one must take into account their availability in the different piconets, which represents a difficult, scatternet wide coordination problem and can be an important performance bottleneck in buillding scatternets. In this paper we propose the Pseudo-Random Coordinated Scatternet Scheduling (PCSS) algorithm to perform the scheduling of both intra- and inter-piconet communication. In this algorithm Bluetooth nodes assign meeting points with their peers such that the sequence of meeting points follows a pseudo random process that is different for each pair of nodes. The uniqueness of the pseudo random sequence guarantees that the meeting points with different peers the node will collide only occasionally. This removes the need for explicit information exchange between peer devices, which is a major advantage of the algorithm. The lack of explicit signaling between Bluetooth nodes makes it easy to deploy the PCSS algorithm in Bluetooth devices, while conformance to the current Bluetooth specification is also maintained. To assess the performance of the algorithm we define two reference case schedulers and perform simulations in a number of scenarios where we compare the performance of PCSS to the performance of the reference schedulers
scheduling bluetooth scatternet inter-piconet communication