Research On QoS-Based Vertical Handover Algorithm For Wireless Body Area Networks

In recent years,Wireless Body Area Network(WBAN)has become an emerging technology in the field of health care.Patients can collect body sensory information for remote monitoring through wearable and implantable body sensor nodes.With the continuous development of coordination equipment installed on patients,the WBAN network in heterogeneous wireless networks can provide physiological parameter information collected by remote terminals at any time.However,in this type of network,providing seamless handover with guaranteed quality of service(QoS),especially for emergency services,is a challenging task.Therefore,the research on vertical handover of wireless body area network is of great significance.According to the characteristics of the data in the wireless body area network,this paper divides the service types into four categories: emergency high-bandwidth services,emergency small-bandwidth services,ordinary high-bandwidth services,and ordinary small-bandwidth services.Different business types have different requirements for data transmission.Two types of emergency services need to be transmitted with low delay in a short period of time,while two types of general services only need to be transmitted within a specified time but may be more sensitive to service prices.Therefore,these four services have different QoS requirements.In view of the current research on vertical handover algorithms for wireless body area network external communication,and multiple attribute decision making(MADM)is often used in vertical handover of wireless heterogeneous networks,in this paper,firstly,based on the service types and different QoS requirements in wireless body area networks,a multi-attribute network selection method and weight determination method suitable for wireless body area networks are studied.In the method of determining the weights,the weights are obtained by using Analytic hierarchy process(AHP),Fuzzy analytic hierarchy process(FAHP),and subjective and objective weighting methods.In the multi-attribute network selection method,they are used separately.In the multi-attribute decision method,the cost function method,the Technology for Order Preference by Similarity to Ideal Solution(TOPSIS)method,and the gray relation analysis(GRA)method are used to study the appropriate weightdetermination method and network simulation method through simulation.The simulation results show that the analytic hierarchy process is an appropriate weight determination method,and the TOPSIS method is a network selection method suitable for wireless body area networks.Wireless body area networks have brought great convenience to areas such as telemedicine and health monitoring.At the same time,there will inevitably be user aggregation situations,such as nursing homes.At this time,multiple users may switch at the same time,that is,group handover.If users switch to the same network at the same time,it is likely to cause network congestion.This article is based on the weight determination method and network selection method developed earlier,and then studies the group vertical handover algorithm of the wireless body area network.In order to avoid multiple users switching to the same network,when a user switches to a certain network,the switching result is broadcast and the network load is updated in real time.Finally,this paper uses OPNET network simulation software to build the LTE-WLAN1-WLAN2 ternary heterogeneous network model.The algorithm is simulated on this platform and the related performance of the algorithm is verified.Simulation results show that the algorithm proposed in this paper can switch to the appropriate network according to user service changes and OoS requirements of different services.After the user switch,the network load situation is successfully propagated.