Scheduling channel time allocations in 802.15.3 WPANs for supporting multimedia applications

摘要

The 802.15.3 standard is a reference point for high data-rate wireless personal area networks (WPANs), being able to support also multimedia applications with specific quality of service (QoS) requirements. In a 802.15.3 piconet, a single piconet co-ordinator (PNC) distributes channel time allocations (CTAs) to devices (DEVs) associated to it, in order to provide the expected QoS. The 802.15.3 standard does not specify how this allocation should be done. To bridge this gap, we propose a dynamic CTA scheduling scheme that provides bounded average delays to multimedia applications. The algorithm is based on a control theoretic approach and acts in two steps: (1) each single DEV computes its transmission needs by applying a control algorithm that targets empty transmission queues; (2) the PNC collects requests of DEVs and allocates CTAs by taking into account the capacity constraints of the wireless channel. The main properties and the tuning rules of the algorithm have been theoretically investigated. Moreover, in order to provide a comprehensive performance evaluation of the proposed approach, realistic scenarios with video, voice, and FTP flows have been simulated using ns-2. Results confirm that our scheduler is able to satisfy the expected delay bounds in a wide range of traffic loads.