An integrated approach to scatternet traffic management in Bluetooth ad hoc networks

Abstract

Bluetooth is an important and increasingly popular wireless communication standard, and in recent years a large number of Bluetooth products have been introduced commercially. Its chief advantages are small and low power consumption, which make the technology an attractive choice when setting up short-range wireless ad hoc networks. A typical Bluetooth network, known as a piconet, consists of one master and seven slaves. When several Bluetooth networks interconnect through a number of bridge nodes, they form a scatternet. However, no routing protocol has yet been defined for Bluetooth scatternets. Meanwhile, because of its small size and low cost, Bluetooth is widely "pervasive", in the sense that even low cost electrical appliances are expected to become Bluetooth enabled. If so, scatternets consisting of several piconets will exist even in a home environment. Thus, there is a pressing need to develop an efficient ad hoc routing algorithm to make effective communication possible between distant devices. This study proposes an integrated ad hoc routing and time-slot scheduling (IARTSS) scheme to address the problem of ad hoc routing in Bluetooth networks. Our proposed scheme contains four main mechanisms to address the different facets of the problem, namely Compensation-Based Time-Slot Assignment (CTSA), Traffic Differentiation Queueing (TDQ), Adaptive Master-Slave Switching (AMSS), and an Enhanced AODV algorithm for ad hoc routing. CTSA judiciously allocates time-slots to slaves based on elapsed time, utilization, and queue lengths, helping the bridge nodes to catch up with the lagging of services in piconets. TDQ differentiates traffic into self-originated and forwarded messages, and serves them in a dynamically adjusted adaptive ratio. AMSS calculates the time for a bridge node to stay in a piconet in a more effective way, based on utilization fraction and queue lengths. Enhanced AODV for ad hoc Routing is implemented as a routing protocol for Bluetooth scatternet. We have built a comprehensive Bluetooth simulator and performed extensive simulations to evaluate the proposed IARTSS. We find that our proposed scheme can perform well under a wide variety of practical circumstances, and provides efficient and high performance intra-piconet and inter-piconet communications. © 2004 Elsevier B.V. All rights reserved.