Scatternet formation of Bluetooth ad hoc networks

Scatternet formation must be addressed before any ad hoc network protocol can be run over Bluetooth. This is due to the frequency hop nature and piconet unit of Bluetooth. In this paper, a protocol stack of Bluetooth group ad hoc network and a "blue-star island" network formation algorithm are proposed. The network formation locates within Bluetooth network encapsulation protocol (BNEP) layer and is beneath the routing protocol. The main task of network formation is to establish and maintain Bluetooth network topology with better performance and in a fast and economic way. The routing protocol is mainly to find the best routes among the existing network topology. The network formation communicates with routing protocol and management entity using "Routing Trigger" mechanism. The "blue-star island" algorithm is a distributed 2-stages scheme. First, a group of neighbour nodes are self-organized into "blue-star island", where the joint node is slave in scatternet. Then, initiated by "Routing Trigger" from routing protocol, blue-star islands are bridged together. The "Routing trigger" can be "Route REQuest" message or "HELLO" message. The design has no assumption on number, distribution and mobility of nodes. We present discussion and simulation results that show the proposed algorithm has lower formation latency, maintain consume and generate an efficient and good quality of topology for forwarding packet.