Remote Health-Monitoring of First Responders over TETRA Links

In this paper, we investigate communication performance of a system for remote health-monitoring of first responders over Terrestrial Trunked Radio (TETRA) radio links. The system features a smart garment that periodically records and sends physiological parameters of first responders to a remote agent, which processes the recordings and feeds back the health-status notifications and warnings in the form of electrotactile stimuli. The choice of TETRA as the connectivity solution is driven by its routine use by first responders, thus representing a convenient and economically-effective connectivity basis. However, the support for data communications in TETRA is limited and in practice reduced to the Short Data Service, which adversely affects the delay and failure probability of the messages exchanges in the system, as shown in the paper. Nevertheless, when the system is examined and optimized in terms of the peak Age-of-Information, a metric suitable to characterize the quasi-periodic nature of the considered monitoring process, we show that its performance becomes rather favorable, enabling timely insights into the first responders' health status.