Bridges of Bluetooth county: topologies, scheduling, and performance

The performance of two Bluetooth piconets linked through a shared device is analyzed using the tools of queueing theory. We analyze both possible topologies: the master/slave (MS) bridge, in which the shared device is the master in one of the piconets and a slave in the other, and the slave/slave (SS) bridge, where the shared device is the slave in both piconets. Two scheduling policies, limited service and exhaustive service, are considered. Analytical results are derived for the probability distribution of access delay (i.e., the time that a packet has to wait before being serviced) and end-to-end delay for both intrapiconet and interpiconet bursty traffic. SS bridge has been found to offer lower access delays and local end-to-end delay than its MS counterpart, which provides lower end-to-end delay for nonlocal traffic due to the smaller number of hops (three, instead of four) for such traffic. In both topologies, exhaustive service scheduling was found to provide lower delays than the limited service one. All analytical results have been confirmed through simulations.