Distributed localization: A comparison of performance limits

We show that the fundamental performance limits, specifically the Cramer-Rao lower bounds (CRLBs), of multihop localization algorithms (MHLAs) and message-passing localization algorithms (MPLAs) can be comparable under some circustances. Although message-passing is the approach currently most often considered for cooperative localization, MPLAs rely on the "diffusion" of the known location of a few nodes (anchors) to the entire network via a typically large number of message exchanges amongst neighbors, resulting in high communications costs, low robustness to mobility, little location privacy to end users and slow convergence. In contrast, in MHLAs each node is localized based on the multihop distances between itself and anchors, such that substantially lower communication costs, intrinsic privacy and faster location-acquisition are inherently achieved. In light of the above, our results advocate in favor of MHLAs as an alternative, fast and energy-efficient approach for distributed localization in many cases of interest.