Four-Bit Wireless Link Estimation

We consider the problem of estimating link quality in an ad-hoc wireless mesh. We argue that estimating links well requires combining information from the network, link, and physical layers. We propose narrow, protocolindependent interfaces for the layers, which in total provide four bits of information: 1 from the physical layer, 1 from the link layer, and 2 from the network layer. We present a link estimator design with these interfaces that reduces packet delivery costs by up to 44% over current approaches and maintains a 99% delivery ratio over large, multihop testbeds.