A holistic simulation model for remote patient monitoring systems using Wireless Body Area Sensor Networks (WBASNs)

摘要

Remote patient monitoring systems mainly depend on the standards and protocols of the Wireless Body Area Sensor Networks (WBASNs). The increasing demand for these systems impose various challenges, including time bounded services, specific data rates, prioritized data transmission and energy consumption, etc. These challenges maps on the different layers of the protocol stack for WBASNs. In this context, a lot of new protocols for applications, MAC, network and physical layer have been proposed; however, few describe a complete simulation model to evaluate patient monitoring system. In this context, this work examines and proposes a simulation model based on the CASTALIA 3.2 simulator with an OMNeT++ framework to evaluate the patient monitoring system. The proposed model consist of six biomedical sensor nodes, including electrocardiography (ECG), blood pressure (BP), accelerometer, temperature, blood oxygen saturation and glucose monitor. The model defines the data rate settings for these nodes at the application layer. All these nodes are configured in star topology and send data to a centralized controller. IEEE 802.15.4 standard is used for the MAC and PHY layer and ZigBee is used over network layer. Slotted carrier sense multiple access with collision avoidance (CSMA/CA) is used as a channel access mechanism, however, the model also accommodate prioritized channel access by configuring guaranteed time service (GTS) for an ECG node. To evaluate the model, the parameters including delay, packet delivery ratio (PDR) and energy consumption is used. To evaluate simulation model over patient monitoring system, we have considered 250 ms as maximum affordable delay. It is observed that most of the nodes delivered data to coordinator under 250 ms Moreover, for the GTS model, the prioritized node (ECG) shows the acceptable delay and PDR values. Further, GTSon mode utilizes less energy as compared to GTSoff mode. Overall, researchers can use this model as a guideline to e- aluate new protocols and standards of WBASNs.