Reducing power consumption and enhancing performance by direct slave-to-slave and group communication in Bluetooth WPANs

Bluetooth is a promising wireless technology aiming at supporting electronic devices to be instantly interconnected into short-range ad hoc networks. The Bluetooth medium access control protocol is based on the Master/Slave concept wherein any communication between slave devices has to go through the Master. While this model provides for simplicity, it incurs longer delay between any two slaves devices due to far from optimal packet forwarding, the use of double the bandwidth, and also wastes additional energy at the Master. Moreover, if more than two devices want to communicate as a group, this can only be achieved by either multiple unicast transmissions or a piconet-wide broadcast, clearly resulting in inefficiency. In this paper, we propose a novel Dynamic Slot Assignment (DSA) scheme whereby the Master device dynamically assigns slots to Slaves so as to allow them to communicate directly with each other without any Master intervention. This proposed communication architecture also provides for Quality of Service (QoS) requests, admission control, and multi-device conversation by which a multicast-like communication is implemented within a piconet. Through extensive simulation, we observe that DSA drastically enhances Bluetooth performance in terms of delay and throughput, while significantly reducing power consumption at the master and also of the overall piconet. (C) 2004 Elsevier B.V. All rights reserved.