Abstract
Nowadays, applications of wearable instruments for remote healthcare have become a highly-valued research and developed the wireless body area network (WBAN). In a remote healthcare system, multiple physiological signals are required to be transmitted simultaneously to a mobile device and be observed in real time. According to the above requirements, we propose a low-power and low time delay MAC protocol. In this thesis, we improve the time division multiple access (TDMA) system. TDMA is a helpful way to save power, but overhead and idle listening problems still exist. Thus, we propose a low cost wakeup radio to connect to the sensor. Wakeup radio makes sensor nodes to be in sleep state when there is no data to transmit or receive. If the system starts to operate, controller will send message to wakeup radio and then the sensors will start to communicate. Therefore, using wakeup radio can not only reduce the overall power consumption, but it can also prolong the lifetime of the network. In the improvement of traditional TDMA, we propose a method to wake up the sensors through wakeup radio, only when the controller wants them to receive data. After the sensor receives wakeup radio, it soon wakes up and starts to communicate. The proposed protocol is more adjustable than traditional TDMA. The number of slots at each frame in our proposed protocol is calculated, as well as the power consumption and time delay, which is compared to other MACs. The packet interval time is regarded as the unit of power consumption in the simulation. The comparison shows that the power consumption of the proposed protocol is nearly one third than that of WiseMAC when the packet inter-arrival time is 10 seconds. Besides, the time delay is 29.76 millisecond and does not vary when the operational time becomes longer. Therefore, it is proved that the proposed protocol achieves a low-power consumption, a low time delay and flexibility for utilization. The proposed protocol greatly enhances the overall system performance.