ITR: Cross-Layer Design of Ad-Hoc Wireless Networks for Real-Time Media

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ABSTRACT0325639Goldsmith, AndreaStanford UniversityAn ad-hoc wireless network is a collection of possibly mobile wireless nodes that self-configure to form anetwork without the aid of any established infrastructure. The lack of infrastructure is extremely compellingfor applications where a communications infrastructure is too expensive to deploy, cannot be deployedquickly, or is simply not feasible. Such applications range from multi-hop wireless broadband Internetaccess to sensor networks to building or highway automation to voice, image, and video communication foremergency response, a life-saving capability urgently needed by our society. The nature of ad-hoc wirelessnetworks makes support of delay-critical applications such as voice and video quite challenging. In thisproject the investigators study a new framework for ad-hoc wireless network design to support such delay-critical applications. The framework includes dynamic allocation of network resources to support mediarequirements, protocols that are robust to variations and uncertainties in the network, and adaptive mediacompression techniques that preserve end-to-end network connectivity even when network conditions arepoor. The results of the project are expected to have a significant impact on the development of futurewireless networks and the enabling of critical applications.The framework being developed to support delay-critical applications in ad-hoc wireless networks is basedon cross-layer design across the network protocol stack. The design incorporates adaptation across multipleprotocol layers, including the application, transport, network, and link layers. Within this framework, theinvestigators develop a suite of new techniques to balance network congestion and distortion of real-timemedia streams by jointly optimizing error-resilient source coding, packet scheduling, stream-based routing, link capacity assignment, and adaptive link layer techniques. The optimization is carried out dynamically by all nodes, based on link state communication, to continuously adapt to changing link and trac conditions.The research project systematically investigates these new ideas and ultimately demonstrates them in a smalltestbed.