Measurement and analysis of UWB radio channel for indoor localization in a hospital environment

This paper focuses on accurate localization of patients in a hospital environment. To reduce power consumption and increase privacy, the localization of patients is only activated in case of an emergency. To evaluate the performance of 'single-shot' localization, ultra-wideband (UWB) radio channel measurements are performed in a modern hospital between a 'mobile agent' and 9 'anchors'. The anchors are placed at existing infrastructure, to allow for easy future integration. The agent is moved over a distance of 40 m at 460 points and spans several furnished rooms and a corridor. The channel is measured from 5 to 10 GHz with a link-budget of 120dB. Using post-processing, the impact of system parameters, like bandwidth and link-budget reduction, on the localization accuracy is evaluated. Our results show that a model based on the logistic distribution yields a higher accuracy, as it more resilient against outliers. The 'single-shot' localization has a mean error of 8.7 cm for a link budget of 110 dB, a bandwidth of 500 MHz, and a carrier frequency of 8.0 GHz. Results show that increasing the bandwidth does not improve the mean localization accuracy. However, reducing the link budget results in a considerably larger mean error.