Performance evaluation of an intention sharing MAC scheme in wireless LANs with hidden nodes

Abstract

We have previously presented Intent, a medium access control scheme for WLANs based on cooperative, distributed, non-binding frame scheduling. The main idea behind Intent is “intention sharing”-a mechanism that allows a node to be aware of transmissions previously scheduled by its neighbors. We now extend this scheme to networks with hidden nodes. We give a formulation of the scheduling problem and solve for the optimal solution using mixed-integer programming in a range of scenarios covering both mesh and infrastructure networks of varying density. We also provide an algorithmic solution and perform simulations using four variants of this, comparing the results with both the optimal solution and standard 802.11. Our algorithmic solution gives significantly better performance than 802.11 and comes within 1.1 times optimal performance when full, two-hop scheduling information is available. In addition, we show that it is not necessary to exchange complete scheduling information in order to perform distributed scheduling effectively but rather a conflict resolution or avoidance mechanism combined with non-binding schedules allows for similar performance with only a single round of information exchange between neighbouring nodes.