A performance comparison of scatternet formation protocols for networks of Bluetooth devices

This paper describes the results of an ns2-based comparative performance evaluation among three major solutions presented in the literature for forming multi-hop networks of Bluetooth devices (scatternet formation). The three protocols considered in this paper are BlueTrees, BlueStars, and the "Yao protocol". We observed that device discovery is the most time-consuming operation, independently of the particular protocol to which it is applied. By means of a thorough performance evaluation we have identified protocol parameters and Bluetooth technology features that affect the duration of this device discovery. We have also analyzed the effect of the different protocols operations on key metrics of the generated scatternets. The comparative performance evaluation showed that due to the simplicity of its operations and to its basic working requirements BlueStars is by far the fastest protocol for scatternet formation which also yields to scatternets with a lower number of piconets, average route length and number of roles per node. However, BlueStars produces scatternets with an unbounded, possibly large number of slaves per piconet, which imposes the use of potentially inefficient Bluetooth operations. A good compromise when interested informing scatternets whose piconets have a bounded number of slaves is obtained by combining BlueStars and the Yao protocol. Although latency and route lengths are longer than in BlueStars scatternets, with the combined solution we obtain an overall good protocol performance and scatternets with desired characteristics.