Edinburgh Napier University

  The link quality protocols of the IEEE 802.15.4 show low performance in terms of reliability in a hospital environment. To achieve the optimal performance of these protocols, this paper proposes a fuzzy logic-based solution using a detailed empirical reliability assessment. This paper provides a solution through four steps: 1) identifying the suitable IEEE 802.15.4 protocols and validating their suitability for patient monitoring systems through simulation in Castalia 3.2 with the OMNet++ platform; 2) providing a detailed discussion and analysis regarding link quality mechanisms used; 3) creating a real-time test bed to perform the empirical experiments to find the actual link quality estimation for different hospital environments; and 4) proposing a fuzzy logic system (FLS), which maps the results of empirical experiments with the proposed FLS to obtain the optimal results. For empirical experiments, we divide the communication in the hospital into four environmental scenarios, including inside ward, corridor, ward to corridor, and ward to ward. Both mobile and static scenarios are considered with line of sight and non-line of sight. Different link quality threshold values for link quality indicator (LQI) and received signal strength indicator (RSSI) are found for the variety of hospital scenarios. A strong correlation is noticed between LQI and packet reception rate in most of the scenarios, whereas a weak correlation is found between RSSI and packet reception rate. Finally, the results are mapped to our proposed FLS to obtain the optimal performance.