Research Of Reliable Transmission In WBAN

With the development of wireless communication and microminiaturization of electronic devices,wireless body area network(WBAN)has attracted more and more attention.WBAN is a kind of small-scale wireless communication network,which is deployed on human body.With the ability to collect and monitor physiological information of human,WBAN has played an increasingly important role both in traditional healthcare field and in emerging consumer electronics devices field.At present,the miniaturization of sensors and the frequent occurrence of multi-network coexistence put higher demands on WBAN energy efficiency and transmission reliability.In scenarios where WBAN users are clustered,such as hospitals and gyms,communication over multiple WBAN coexistence can have a significant impact on energy efficiency and transmission reliability.In the multi-network coexistence scenario which considers dynamic channel,the traditional TDMA-based power control algorithm can not guarantee the timeliness and accuracy of the channel prediction value for increasing sensors and channel fluctuation,which causes the reduction of successful transmission.A WBAN power control algorithm based on hybrid access mechanism is proposed for multi-network coexistence scenario considering dynamic channel in this paper.This algorithm determines the channel stability by analyzing the channel history data and make sensors adopt different access mechanisms according to their channel stability,which takes advantage of the low energy consumption of TDMA and the real time feedback characteristics of CSMA/CA.The algorithm improves reliability while maintaining energy efficiency by adjusting transmission power according channel prediction on stable channel and according real time path loss on dynamic channel.To mitigate the homogeneous network interference in the multi-network coexistence scenario,the current node-level interference mitigation algorithm reuses the time slot of the noninterfering node to improve the channel reuse rate while avoiding interference.However,this type of algorithm introduces the unfairness of time slot resource allocation and causes the overall performance degradation of the network when the number of networks increases.In this paper,the probability theory is used to analyze the channel reuse rate and the fairness of time slot allocation in the node-level interference mitigation algorithm.A novel node-level interference mitigation algorithm is proposed in this paper for the case that the existing algorithm is not fair in time slot resource allocation.The algorithm reduces the time slot resource allocation gap between the interfering node and the non-interfering node by reducing the redundant time slot allocated to the non-interfering node,which improves the fairness of the slot allocation.As a result,this algorithm can improve the network performance while maintaining the channel reuse rate.Finally,this paper validates the effectiveness of the power control algorithm based on hybrid access mechanism and the interference mitigation algorithm based on the fair time slot allocation by constructing WBAN system simulation platform.The simulation results show that the power control algorithm based on hybrid access mechanism can improve the reliability of transmission while maintaining high energy efficiency.And the interference mitigation algorithm based on fair slot allocation improves the fairness of time slot resource allocation while maintaining higher channel reuse rate.