Optimization of 2d virtual node coordinates in anchor-free localization algorithms for geographic routing in ad-hoc networks

Many localization algorithms require that at least some nodes in a network know their correct real position. Anchor-free localization algorithms manage to assign to all nodes virtual coordinates (VC) without knowledge of real location information. This is mostly done by node cooperation. These algorithms provide VCs for the usage of geographic routing in environments where real coordinate localization is impossible due to cost, time, energy, space or line of sight restrictions. This paper proposes improvements in generating VCs for wireless ad-hoc networks without location information. We present algorithms for improving the preparatory phase, which is used to obtain initial VCs as well as for the working phase, which adapts to network changes and node movement. Using simulations for different node densities and network sizes, we compare different approaches and show which algorithms outperform others.