Decision of Ranging Interval for IEEE 802.15.4z UWB Ranging Devices

Recently, many researchers and global vendors of mobile devices have paid attention to the ranging technique using IEEE 802.15.4z ultra-wideband (UWB), because it can support a highly precise spatial awareness and indoor localization. In the Internet of Things (IoT) environments, the interval of the ranging attempts for a ranging device (RDEV) affects largely the performance of the RDEV. The proper ranging interval for an RDEV varies according to the IoT applications using the ranging results as well as the type and state of the RDEV (e.g., moving speed and battery status). In the IEEE 802.15.4z, since the ranging for a group of multiple RDEVs is carried out once every ranging block, the ranging interval can be represented by the block length, which should be determined based on the various requirements of RDEVs within the group. In this article, we analyze the requirements on the block length of RDEVs, from the viewpoint of the energy efficiency and the degree of service satisfaction. Considering these requirements, we design a novel decision scheme of the ranging block length, based on the Markov decision process. The simulation results show that the proposed scheme enhances remarkably the energy efficiency and the satisfaction of RDEVs.