Research On MAC Protocols For Wireless Body Area Networks Based On IEEE 802.15.6

Wireless body area network(WBAN)is a short-distance communication network formed by sensor nodes deployed in the body or body surface and body surrounding devices.The network is mainly used to monitor human physiological data or surrounding environment information,and can be applied to many fields such as medical treatment,sports,entertainment,and so on.The sensor nodes of the WBAN are powered by batteries,which are not easy to charge or replace the battery,and the data transmission needs high real-time performance,therefore,reducing delay and energy consumption is the research focus of the wireless body area network MAC protocol.IEEE 802.15.6 is a communication standard for WBAN that supports shortrange,low-power,and high-reliability wireless communications.Therefore,we mainly studies MAC protocols for WBAN based on IEEE 802.15.6.We first analyze the network architecture and characteristics of the WBAN and the basic theory of the MAC protocol of the WBAN based on the research status of the MAC protocol of the WBAN,and the IEEE 802.15.6 specification is mainly studied.Based on this,aiming at the problem of low adaptability and low energy efficiency of MAC protocol of the WBAN,we proposes an adaptive WBAN MAC protocol(AMAC).The protocol adopts a simplified superframe structure based on IEEE 802.15.6,to reduce control overhead and simplify control difficulty.In order to ensure the realtime and reliability requirements of high-priority services,high-priority data is designed to be transmitted in contention access phase;at the same time,based on the service priority for dynamic time slot allocation,improve network adaptability and time slot utilization.The simulation results show that he network performance using A-MAC protocol is significantly better than the network performance using IEEE 802.15.6 MAC protocol and CA-MAC protocol.Then,in order to solve the data delay problem of nodes during periodic sleep,a wireless body area network MAC protocol based on wake-up mechanism(W-MAC)is studied.The protocol is based on the IEEE 802.15.6 standard and adopts wake-up mechanism.All nodes add an extra ultra-low-power wake-up circuit,and the node is always in a sleep state when there is no data transmission,which can effectively reduce the network energy consumption.According to the service priority situation,different wake-up methods are adopted: for periodic services,the coordinator initiates wake-up to the node,and the node initiates wake-up to the coordinator for random services.In addition,in order to reduce data collision,when two or more nodes are awakened at the same time,high priority services are preferentially processed.The simulation results verify that the W-MAC protocol can significantly reduce network energy consumption and improve overall network performance.Finally,in order to solve the contradiction problem of energy efficiency and delay of WBAN,a multi-channel WBAN MAC protocol(MC-MAC)is proposed.The protocol adopts a multi-channel mechanism to divide the channel into one management channel and multiple transmission channels,which can effectively avoid interference and reduce network delay;add a channel state field in the beacon frame to map channel state and obtain channel idle condition.At the same time,the number and priority of nodes are comprehensively analyzed,and the initial channel is allocated to the node,so that the node is preferentially transmitted on the initial channel.In addition,a channel selection mechanism based on node priority is proposed to avoid collision.The simulation results show that the MC-MAC protocol significantly improves network performance in terms of network delay,average power consumption and normalized throughput.