 
Summary: Corrective Consensus with Asymmetric Wireless Links
Yin Chen Roberto Tron Andreas Terzis Rene Vidal
yinchen@cs.jhu.edu tron@cis.jhu.edu terzis@cs.jhu.edu rvidal@jhu.edu
Computer Science Department Center for Imaging Science
Johns Hopkins University
Abstract Consensus algorithms can be used to compute an
average value across a multihop network in a distributed way.
However, their convergence to the right value is not guaranteed
in the presence of random packet losses that are common
in real life lowpower wireless networks. Corrective consensus
solves this problem by using a set of auxiliary variables to
compensate for the asymmetric state updates caused by packet
losses. Nevertheless, one key assumption is that the probability
of delivering a packet from node i to a neighboring node j is the
same as in the reverse direction, from j to i. This assumption
might be violated in real life conditions. Our main contribution
is showing that corrective consensus converges to the correct
average even when this assumption is removed. In addition, we
provide a heuristic for modifying the weights used by corrective
consensus that specifically considers the unequal probabilities,
