Cooperative Localization in WSNs: A Hybrid Convex/Nonconvex Solution

We propose an efficient solution to peer-to-peer localization in a wireless sensor network that works in two stages. At the first stage the optimization problem is relaxed into a convex problem, given in the form recently proposed by Soares et al. The convex problem is efficiently solved in a distributed way by an alternating direction method of multipliers approach, which provides a significant improvement in speed with respect to the original solution. In the second stage, a soft transition to the original, nonconvex, non-relaxed formulation is applied in such a way to force the solution toward a local minimum. The algorithm is built in such a way to be fully distributed, and it is tested in meaningful situations, showing its effectiveness in localization accuracy and speed of convergence, as well as its inner robustness.