XPRESS for Wireless Multi hop Networks

Abstract

Our current theory integrates three functions—congestion control, routing and scheduling in transport, network and link layers into a coherent framework. Within this context, this model allows us to systematically derive the layering structure of the various mechanisms of different protocol layers, their interfaces, and the control information that must cross these interfaces to achieve a certain performance and robustness. Transmissions over the network are scheduled using a throughput-optimal backpressure algorithm. Realizing this theoretical concept entails several challenges, which we identify and address with a cross-layer design and implementation on top of our wireless hardware platform. In contrast to previous work, we implement and evaluate backpressure scheduling over a TDMA MAC protocol, as it was originally proposed in theory. Our experiments in an indoor test bed show that XPRESS can yield up to 128% throughput gains over 802.11.