Capacity and Delay Tradeoffs for Wireless Multihop Networks

Contemporary wireless multihop networks operate much below their capacity due to the poor coordination among transmitting nodes. Cross-layer architectures offer a radical alternative by advocating cooperation among the multiple layers of the protocol stack. At the center of these architectures is the backpressure scheduling algorithm which accomplishes the system limit. XPRESS is throughput-optimal backpressure architecture for wireless multihop networks. XPRESS is composed of a central controller, which performs backpressure scheduling based on the measured wireless network state, and also of the wireless nodes, which periodically provide the network measurements and execute the computed schedule using a cross-layer protocol stack. One of the main drawbacks of this scheme is delay reduction. Delay reduction techniques provide better delay performance than traditional backpressure in terms of the maximum throughput.