MAC Protocol Design for Optical Wireless Body‐Area Networks: Latency, Energy Efficiency and Scalability Analysis

ABSTRACT This work considers the use of optical wireless communications (OWC) for transmitting data from medical devices in wireless body‐area networks (WBANs) for the purpose of patient vital sign monitoring. In such networks, the design of efficient medium‐access control (MAC) protocols is crucial to ensuring reliable and effective data transmission from multiple nodes. Here, IEEE 802.15.6 and IEEE 802.15.7 standards, developed for wireless personal area networks (WPANs), are compared and evaluated through numerical simulations to assess their suitability for the specific use‐case under consideration. The former standard was initially developed for radio‐frequency (RF) networks, whereas the latter is based on OWC technology. This work also provides insights into the performance of the recently‐introduced IEEE 802.15.13 standard, designed for optical WPANs. Our study relies on the Castalia simulator, combined with realistic optical WBAN channel models developed in our team's previous works, with network energy efficiency and quality‐of‐service (QoS) serving as the primary evaluation criteria. Both cases of intra‐ and extra‐WBAN connectivity are considered, where the former refers to data transmission from medical sensors to a coordinator node (CN), and the latter to transmission from CNs (each corresponding to a patient) to an access point (AP), in a hospital ward, for instance. Additionally, two scenarios are examined: battery‐operated CNs and power‐outlet‐connected CNs, with the latter assumed to be positioned on the patient's beds in an intensive care unit (ICU) room. Our results show the advantage of the IEEE 802.15.7 MAC protocol in terms of both energy consumption and QoS, for all considered scenarios. Finally, because the number of patients may vary across hospital wards, the scalability of the aforementioned MAC protocols is also investigated by varying the number of patients up to 8. The results indicate that IEEE 802.15.13, which relies on time‐division multiple access (TDMA), is a viable candidate for optical WBANs despite its limited scalability, which could be resolved using a more flexible allocation of time resources to ensure that all nodes are granted access to the transmission time slots. Overall, this study advances current knowledge and offers new insights into the design of robust optical WBANs that can ensure acceptable QoS under varying conditions while preserving energy efficiency, enabling their practical deployment in real‐world healthcare scenarios.