Reliable and Energy Efficient MAC for Medical Body Area Networks for Patient Monitoring in Hospitals

Abstract

In medical body area network small sized medical sensors are attached to a patient's body for continuous and real-time monitoring of biomedical vital signs. These nodes collect data from patient's body and send it to base sta- tion via intermediate node so that doctors/caregivers can access the patient's data or can be timely informed if any patient's condition goes critical. But due to the small size, these sensor nodes have low data rates, small transmis- sion ranges, limited battery power and processing capabilities etc. On the other hand reliability is most important issue in medical body area network because of critical nature of patient's data. Any wrong or missing or delayed data can create a situation in which doctors or caregivers may take wrong decisions about patient's health which can have fatal results. Reliability of data transmission can be ensured on the cost of power consumption in net- work by using di erent methods such as retransmissions, acknowledgments and guaranteed time slot mechanism etc. We propose an e cient MAC to achieve both reliability and energy e ciency in medical body area network at acceptable trade-o levels. The Proposed MAC not only overcomes the limitations of existing ZigBee MAC such as ine cient CSMA/CA mechanism and underutilization of guaranteed time slots but also it adapts di erent traf- c types such as emergency tra c and normal tra c. The proposed MAC is implemented in Castalia simulator and simulations results show that the application level throughput and packet delivery ratio of network increase and packet loss rate decreases at MAC level. We also optimize the energy utilization of network by reducing the number of retransmissions and also by tuning the parameters of ZigBee MAC i.e. macMaxCSMABacko s and macMinBE.