QoS Provisioning for H.264/SVC Streams over Ad-Hoc ZigBee Networks Using Cross-Layer Design

The ZigBee ad-hoc network is a collection of mobile wireless sensors that are self-configurable to form a network without relying on any infrastructure. The absence of the infrastructure, the network and channel dynamics, the limited bandwidth and packet size, and the nature of the wireless medium offer an unprecedented set of challenges in providing video streaming over such networks. Therefore, providing efficient quality of service (QoS) support in this type of networks is essential, as they need to deliver real-time services along with the traditional data service. In this paper, to improve the quality of the H.264 Scalable Video Coding (SVC) streams that are being transmitted over ZigBee ad-hoc network, we propose a cross-layer design framework where the information is exchanged between application layer, MAC layer and the interface queue sub-layer. The quality_id (QID) of the video frame, the Number of Back-off (NB) and the queue length are used as the cross-layer information to make priority decisions. The video streams are encoded using SVC encoder with medium-grain scalability (MGS), and the simulation results prove the validity and effectiveness of our design.