Simulation of ISO/IEEE 11073 Personal Health Devices in WBANs

Simulating new protocols for e-health systems is very important, as it allows an initial evaluation before a real implementation is made. On the other hand, network simulators do not offer proper support to represent medical applications or components to facilitate running simulations modeling e-health applications. The lack of simulators that specify the sensor type and its communication requirements make real experiments harder. Aiming at fulfilling this gap, this paper proposes the use of ISO/IEEE 11073 standard for Personal Health Devices (X73-PHD) in e-health network simulations, representing realistic medical applications and investigating the behavior of medical devices (sensors or actuators) in Wireless Body Area Network (WBAN) scenarios. We developed a free and open-source implementation of X73-PHD for Castalia Simulator, providing five different PHD types to act like real ISO/IEEE 11073 devices in WBAN simulations. Our implementation supports Agent-initiated mode, where PHDs take the initiative to send measurements to the hub. Our implementation also supports the unconfirmed communication mode and the confirmed communication mode, where the receiver sends an acknowledgment to the sender every time it receives a packet. Simulation results showed that the confirmed communication mode did not perform well in WBANs when the interval between transmissions is too small, due to the long period of timeout proposed in the X73-PHD standard. Therefore, we propose a new extension to the confirmed mode standard that decreases the overhead of control packets over the network, using smaller timeouts and delivering more packets.