Interference Mitigation Technologies In Coexisting WBANs

With the development of medical internet in recent years,Wireless Body Area Network(WBAN)plays an crucial role in medical environment.A typical WBAN system consists of a central coordinator Hub and Nodes attached to the surface or implanted in human body.With the development of micro-electronics and wireless communication technologies,WBAN can not only be used as a traditional medical applications,but also applications in industrial production environment and the recreational activities of human beings.When WBANs appear in other wireless system's coverage using the same or similar channel,the whole network performance will suffer performance degradation due to the interference in the wireless channel,the user experience is therefore greatly reduced,so the research of interference mitigation technology in WBANs is of great importance.Taking the interference scenario when multiple WBANs coexist into account.This thesis focus on the interference mitigation techniques within coexisting WBANs.Given the traffic arrival rate of different nodes is not the same,we design a scheduling algorithm named FTAIM(Fast Traffic Adaptive Interference Mitigation)which considers traffic rate and packet reception ratio of different nodes.Then we propose a hybrid medium access control algorithm named DIM(Decentralized Interference Mitigation)which considers the interference level,user priority,and packet queue length: DIM(Decentralized Interference Mitigation).FTAIM allocates the slot according to the slot utilization,and the slot utilization reflects the traffic and interference of wireless channel.According to the slot utilization of different nodes,FTAIM consists of three different states: fast start,flow control and interference mitigation.At first,Hub will allocate one slot per node,and dynamic slot adjustment will be introduced for the following superframe.The core idea of FTAIM is: when the slot utilization above a default upper threshold,Hub will allocate more slots in the next superframe.While decreasing the slots if the slot utilization below a default lower threshold.The simulation results indicates the efficiency of FTAIM would get 87.5%.In DIM,hub will adjust the length between SP and CAP dynamically according to its recent network performance.Specifically,the length of SP will be reduced when the channel utilization in SP decreases,and will be expanded on the contrary.DIM combines the SINR and interference performance.Nodes in the overlapping region tends to be interfered and will get lower access priority.Hub allocates the slots to the nodes based on the DIM algorithm.The simulation results show that the DIM algorithm archive much higher throughput and lower latency under the interference scenario.