Multihop versus message-passing: a complexity and accuracy comparison for distributed localization

In this paper we present the multihop-approach as a complexity and energy-efficient alternative to the classical message-passing scheme in distributed localization for wireless sensor networks (WSNs). While it is the approach currently most often considered for cooperative localization, message-passing localization algorithms (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 multihop localization algorithms (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. Based on the fact that the Cramer-Rao lower bounds (CRLBs) of MHLAs and MPLAs are comparable in most cases of interest, we demonstrated via simulations that from a complexity and energy-efficiency point of view, MHLAs with higher signalto- noise ratio (SNR) but “near-zero” communication costs are a valid alternative to MPLAs.