Flip-MAC: A density-adaptive contention-reduction protocol for efficient any-to-one communication

As Wireless Sensor Network (WSN) deployments increase in density, we foresee a need to divide the problem of Medium Access Control into two steps: the first quickly reduces the level of contention from hundreds of nodes to a handful, while the second relies on existing techniques to select a single node for communication. In this paper, we propose the Flip-MAC mechanism, which takes advantage of non-destructive interference from multiple transmitters to reduce contention to manageable levels in logarithmic time with respect to the initial contention level. We present a description of this protocol and its intended usage, a theoretical description of its operation, simulation results, and an evaluation based on a testbed deployment with actual mote hardware.