Design Of MAC Protocol Based On Multi-Channel Technology In WBAN

Wireless Body Area Network(WBAN)is a human-centered RF based wireless communication network technology,which has the characteristics of high reliability and low power consumption.The sensor nodes are placed in the body or the body surface or around the human body to form a wireless network which can continuously monitor the physiological or environmental signals of the human body,and realize the data exchange between the sensor nodes and remote devices.In the medical field,the patient's physical information can be collected and monitored remotely in real time by this way.Obviously,the implementation of various applications in the network is inseparable from the real-time,reliable and efficient transmission of multimedia content such as data,pictures and video.In view of the characteristic of WBAN's working environment and scenes,it is vulnerable to interference from neighboring networks and other wireless signals.This will lead to partial data loss or transmission timeout and result in unpredictable consequences.In addition,each sensor node in the WBAN is powered by a battery with limited energy,However,the sensor nodes deployed in the body do not allow frequent replacement of the battery.At the same time,sensor nodes deployed in different locations in WBAN will generate multiple types of services,and the service quality requirements of each service are not exactly the same.In addition,the burstiness of the traffic puts higher demands on the performance of the network.In view of the above problems,this thesis starts from the following two aspects:On the one hand,in order to alleviate the interference caused by the use of the same or similar spectrum resources in each node of WBAN,this thesis designs an Interference Mitigation MAC Protocol(IMMAC),which mainly includes:(1)According to the channel condition,the channel is well divided and the channel state analysis scheme is proposed;(2)A more efficient channel selection mechanism is designed in view of the unfairness caused by the different traffic priorities;(3)Channel switching probability parameters are introduced and an effective collision avoidance mechanism is proposed.On the basis,the theoretical analysis framework of the whole communication process is established,and the network normalized throughput and delay are deduced theoretically.Finally,the above two performance indicators are simulated and evaluated.It is proved that the IMMAC protocol can effectively alleviate interference and improve the overall performance of the network.On the other hand,because of the dynamic change of the network topology and the variability of the wireless channel conditions in WBAN,it is not always possible to achieve high energy efficiency and transmission efficiency by deciding the order of data transmission from the priority of users themselves.This thesis proposes a multi-channel MAC Protocol towards Energy Efficiency and Low Interference(EIMAC).Considering the residual energy,traffic priority and volume of the node,a new emergency factor is introduced to determine the order of data transmission of each node,i.e.,the priority of each node is adjusted adaptively.On the basis,the theoretical analysis framework of the whole communication process is established,and the network normalized throughput,delay and energy consumption are deduced theoretically.Finally,the above three performance indicators are simulated and evaluated.It is proved that EIMAC protocol based on efficient transmission mechanism can improve the energy efficiency and transmission efficiency of nodes.