On the scheduling of ranging and distributed positioning updates in cooperative IR-UWB networks

The recent demonstration of precise ranging measurements through low power low data rate (LDR) impulse radio-ultra wideband (IR-UWB) communications has disclosed new perspectives for cooperative location-enabled wireless networks. With this respect, joint ranging and distributed positioning mechanisms supported by specific protocol transactions have already been proposed within user-centric infrastructureless applications. However, in spite of advanced medium access techniques, those approaches still suffer from resource inefficiency. In this paper, we describe and compare new scheduling strategies regarding the joint update of ranging measurements and positional information. One goal is to accelerate the convergence of positioning errors and hence to reduce network latency and overhead accordingly. As an example, one scheduling option considers discarding so-called useless pair-wise links based on the prior analysis of the conditional Cramer Rao lower bound (CRLB) of positioning errors at each mobile node.