Energy Efficient MAC For Wireless Body Area Networks And Application In Mobile Medical

With the continuous improvement of social economy and rapid development of health information technology, physical health has been paid more and more attention. In modern society, population aging is accelerating and the number of patients with chronic diseases is increasing, such as hypertension and hyperglycemia. Mobile medical application based on body area networks has become a new hotspot and is regarded as the effective measure for the lack of medical resources in developing countries and the imbalance between doctors and patients. Wireless body area networks are based on human body and consist of many wireless sensor nodes. It can be widely used in many fields, such as medical, military, sports and entertainment. Compared with traditional sensor networks, wireless body area networks have significant differences. Battery capacity of micro sensor nodes is limited, especially the embedded sensor nodes, so an energy-efficient network is necessary. How to reduce power of nodes has become an important issue in wireless body area network.Firstly, a TDMA MAC Protocol based on multi-superframe is used to decrease the synchronization times of wake-up sensor nodes, which can reduce energy consumption.This muli-superframe protocol incorporates a novel synchronization mechanism where a node can sleep through a number of beacon periods without losing synchronization.Secondly, taking into account the fact that wireless body area networks have low energy consumption, data retransmission and idle listening result in energy wastage. We present a protocol based on master-slave star network. The protocol adopts a TDMA admission control policy and adaptive guard band algorithm. It also can modify the width of guard band dynamically, in order to extend the life circle of wireless body area networks. From the results of simulation, the algorithm based on TDMA can save the energy of nodes. In addition, the protocol can provide slots for urgent data under low-power consumption condition, which meets the requirements of real-time and reliability.At last, we design mobile medical system application based on wireless body area networks. It collects many physiological parameters in human body by wearable medical sensor, such as blood pressure, blood oxygen and ECG. The physiological parameters are transmitted to the intelligent terminal with wireless gateway, and to the cloud platform finally. Health data can be feed back to users and doctors with cloud services layer for the purpose of health surveillance.