High Efficiency And Energy Saving MAC Protocol Based On Multi-channel Strategy In Wireless Body Area Networks

In recent years,the application of wireless body area network(WBANs)in medical and health care has increased rapidly.WBANs consist of intelligent wireless sensor nodes,which can be used to sense and send important physiological data.Wireless body area networks monitoring by used to supervise vital signs sensor node of human body in or around the outside body,which can collect and send patient's information in a timely and effective manner.In a wireless body area network system,sensor nodes should not interfere the users' daily activities,and should be battery-powered to work for days or even months for a single charge,which requires the wireless sensor nodes to be small size and low power consumption.WBANs depends on limited resources,such as energy and bandwidth.In WBANs,The MAC protocol is responsible for nodes' collision detection and processing,priority control,time slot allocation and nodes' transmission order.Thus,The design of medium access control(MAC)protocol plays an decisive role in the reliability and efficiency of wireless body area network.Therefore,in order to effectively use these resources,we must design a very good MAC protocol.At present,although a lot of work has been interested in the energy efficiency of wireless body area networks,only a few work has considered the signal interference between the sensor nodes and the multi-channel solution.Some existing MAC protocols only consider single channel,which can lead to low energy efficiency and channel conflict.At the same time,low latency is an important factor to be considered in the design of MAC protocol in wireless body area networks,Data for different medical applicatons have different transmission cycles and transmission requirements,non-urgent information and non-realtime information only need to be sent as best as possible.While,Important vital signs and real-time information need to be transmitted at the lowest latency,and data collisions and packets loss should be avoided.In this paper,a new MAC protocol named MC_MAC protocol for wireless body area network is proposed,MC_MAC protocol is based on IEEE802.15.6,which is the international standardization specifically designed for WBANs.MC_MAC protocol uses multi-channel communication,which divides the channels into the management channels and the data channels to avoid interference and reduce packets delay.An efficient channel assignment strategy is proposed by dynamically updating the channel condition.Nodes contend to reserve data channels in management channel while transmit data frames through the specified data channels.Meanwhile,the nodes do not need to contend the only single channel,so it is unnecessary to back off under the CW value set before.Finally,the simulations in this paper are conducted by Castalia 3.2 simulator under the environment of Omnet++4.6.By analyzing the comparison between the MC_MAC protocol and typical IEEE802.15.6 in latency and energy consumption,the simulation results show that the MC_MAC protocol is much better than that of IEEE802.15.6 in terms of latency and energy consumption.