A routing protocol and energy efficiency techniques in Bluetooth scatternets

In this paper, we propose a protocol for routing in Bluetooth scatternets. The protocol uses the available battery power in the Bluetooth (BT) devices as a cost metric in choosing the routes. We evaluate the throughput performance as a function of packet arrival rate and number of piconets. A throughput of about 120 kbps/piconet is shown to be achieved in a 5-piconet scatternet. We propose two techniques, namely a) battery power level based master-slave switch and b) distance based power control, to increase the network lifetime in scatternets. The master-slave switch technique is motivated by the fact that a piconet master has to handle the packet transmissions to/from all its slaves, and hence may drain its battery soon. We propose a role switching idea where each BT device in a piconet may have to play the master role depending on its available battery power. In the second technique, we propose that the BT devices choose their transmit powers based on their distances from their respective masters. Our performance results show that a considerable gain in network lifetime can be achieved using these two power saving techniques