Realizing airtime allocations in multi-hop Wi-Fi networks: A stability and convergence study with testbed evaluation

Abstract

REACT is a distributed resource allocation protocol used to negotiate a max–min allocation of airtime for multi-hop ad hoc wireless networks. Two approaches are proposed for a node to realize its REACT allocation in a contention-based MAC protocol. This is achieved by tuning its contention window to a value that corresponds to its allocation. Only a change in the allocation, due to a change in local traffic requirements or local network views, results in re-tuning. The approaches for tuning are implemented in commercial Wi-Fi devices and their stability and convergence are studied experimentally in the w-iLab.t wireless network testbed. These properties are also studied analytically to support the experimental results. In addition, REACT is extended to support airtime reservations for multi-hop flows. With a reservation in place, multi-hop TCP flows exhibit improved performance metrics when running over REACT than when running over 802.11 DCF in the w-iLab.t testbed.