Asynchronous TDMA ad hoc networks: scheduling and performance

Abstract

A common assumption of time division multiple access (TDMA)-based wireless ad hoc networks is the existence of network-wide slot synchronization. Such a mechanism is difficult to support in practice. In asynchronous TDMA systems, each link uses a local time slot reference provided by the hardware clock tick of one of the node endpoints. Inevitably, slots are wasted when nodes switch time slot references. This restricts the rate allocations that can be supported when compared to a perfectly synchronized system. To address this practical performance issue, we first introduce a general framework for conflict-free scheduling in asynchronous TDMA networks. We then propose scheduling algorithms that target overhead minimization while ensuring upper bounds on the generated overhead. Through extensive simulations the algorithm performances are evaluated in the context of Bluetooth, a wireless technology that operates according to the asynchronous TDMA communication paradigm. Copyright (C) 2004 AEI.