Bluetooth: networking and performance

Bluetooth is a promising new short-range wireless technology whose initial purpose was to replace cables between electronic devices. As Bluetooth finds its way into a growing number and types of devices, it can engender and support a whole new range of applications. One such application scenario is that of the PAN (Personal Area Network), which is a network seamlessly connecting devices that a person carries around in his every day life both for work and pleasure. The simplest way in which the devices of a PAN can connect to each other is through a piconet, which is the basic unit of operation in Bluetooth. We present an overall evaluation of the suitability of Bluetooth as a PAN-enabling technology. The networking capabilities of Bluetooth are further enhanced by interconnecting piconets to form scatternets. Examples of the use of scatternets are in a conference, where an on-the-fly scatternet will allow Bluetooth-enabled users to share information such as visiting cards, multimedia files etc. An efficient operation of scatternets requires a number of issues to be solved, and we propose solutions for some of these. The mobile user of today can be connected through various possible wireless interfaces such as 802.11b, Bluetooth, 1xRTT, GPRS etc. For application servers, knowing the capacity of the wireless link, which is likely to be the narrow link on the path, can be useful. With this information, multimedia servers, for instance, can use appropriate streaming rates to the mobile user. We present a capacity estimation methodology we call CapProbe, that is simple, scalable and accurate across a very wide range of experimental scenarios, including wireless. Lastly, there has been huge growth in both multimedia streaming content as well as wireless technologies (such as 802.11b, Bluetooth and 2.5G) and the convergence of the two has generated lot of interest. Yet, problems abound in facilitating this convergence due to the unpredictable, time-varying nature of the wireless medium. We propose solutions to enable the support of multimedia streaming over Bluetooth by enhancing the link layer of Bluetooth. Implementation of our solutions in a Bluetooth testbed shows considerably better support for multimedia.