A Scatternet Formation Algorithm For Solving A New Emerging Problem

Bluetooth, the new technology named after the 10th Century Danish King Harold Bluetooth, is an always on, low-power, and short-range radio technology, aiming at simplifying short-range communications among fixed and mobile devices. Since Bluetooth is cheap and low-power, it has seen continued success in recent several years, and over one billion Bluetooth-based devices are expected to ship in 2008. However, Bluetooth Special Interest Group (SIG) only defines the formation of a small network, which is called Piconet and can only have up to eight devices. The formation of bigger network, which is called Scatternet for creating Personal Area Networks (PAN), remains open, and it has become research hot-spot in the last several years.Thought many concrete protocols of Bluetooth Scatternet Formation have been provided by distinguish researchers, and these protocols concern about many problems: centralized or decentralized, degree limited or not degree limited, different topologies, scalability and performance, almost all these Bluetooth Scatternet Formation Algorithms assume devices are homogeneous. Even the exceptional algorithms barely mentioned a little about the different hardware characteristics of devices for special nodes like bridge nodes or super nodes, which are usually the bottleneck in the scatternet.In this paper, we will first introduce the classification of devices into the formation of Bluetooth Scatternet. We treat the devices differently not only based on hardware characteristics, like computational abilities, traffic load, network bandwidth etc, but also considering virtual properties, like different classes, different groups, different countries and so on. When form the scatternet, the ideal situation is only to connect the devices of the same kind, but in order to guarantee connectivity, we may also need to involve devices of other kinds. One of the goals of this paper is to make such devices least. After integrating classification into Bluetooth Scatternet Formation, we can assure the bottleneck least, this improves the performance. Another achievement is that, we mostly sending messages to necessary devices, and this can reduce message number, total time and energy consuming.We use two ways to tag the devices: one is to set the device name; the other is providing a hash function. After classification, we use a two-phase Scatternet Formation Algorithm. The first phase we will utilize a traditional Scatternet Formation Algorithm, but we will modify the connect function to ensure only the same kind devices can be connected, this will result in several separate scatternets. The second phase is to ensure the connectivity. We will use other kinds of devices as bridge nodes to connect the scatternets. Our goal is to make the bridge nodes least.