An algorithm to arbitrate multiple chirp-spread-spectrum nodes for ranging: The three node case

Chirp-spread-spectrum (CSS) defined in IEEE 802.15.4a is available for ranging based on the time-of-flight of electromagnetic signal and it can be applied to localization systems. One of problems of the CSS-based localization system is the collision of signals transmitted from multiple CSS nodes. In this paper, a probabilistic arbitration algorithm is proposed to prevent the signal collision for ranging. By using the algorithm, we can adjust the probability that each node will succeed in ranging. Therefore, the proposed algorithm can assign higher priority to a node which requires frequent coordinate calculations such as a rapidly moving mobile robot. Through simulations and experimental results, we evaluate and discuss the performance of the proposed algorithm.