Research On Dual Channel MAC Protocol In Terahertz Communication Network

With the birth of virtual reality,augmented reality and other real-time applications,people’s demand for high speed is increasing,but also accelerate the development of the next generation of wireless communication technology.Based on this,a large number of scholars have begun to study wireless communication technologies related to Terahertz(THz)communication.However,the high frequency of terahertz waves and the characteristics of being easily absorbed by water molecules result in a relatively short propagation distance,the terahertz dual-channel media access control(MAC)protocol extends its propagation distance through directional transmission when using terahertz waves to transmit data.Based on the in-depth study of the THz dual-channel MAC protocol,this thesis proposes two improved THz dual-channel MAC protocols for the shortcomings of the existing THz dual-channel MAC protocols.The main research work is as follows:1.For the problems of beam overlap interference and inapplicability in non-line-of-sight(NLOS)environments in the existing dual-channel MAC protocol of terahertz communication networks,a high throughput terahertz dual channel MAC protocol based on relay transmission(HT-RMAC)is proposed.The HT-RMAC protocol includes four new mechanisms: Firstly,the beam interference prediction mechanism is used to determine whether there is beam overlap interference when the source node and the destination node transmit data in the THZ channel.Then the relay node is selected by the relay assist mechanism and the data sent by the source node is forwarded to the destination node through the relay node.Secondly,NLOS environment detection mechanism is used to determine whether NLOS environment exists in the communication channel between source and destination nodes.Finally,when the power of the source node is sufficient,the simplified TTT frame is sent to the source node through the destination node to reduce the overhead.The theoretical analysis and simulation results show that the network performance of the HT-RMAC protocol,such as MAC layer throughput and message transmission success rate,is improved compared with the existing THz dual channel MAC protocol.2.Aiming at the problems of too many interaction times and redundant control overhead in the existing two channel MAC protocol of terahertz communication network,a low overhead high-efficiency terahertz dual channel MAC protocol(LE-MAC)is proposed.The LE-MAC protocol includes two new mechanisms: Firstly,the mechanism of omitting CTS/ACK frame based on node information is used to determine whether the source node can transmit data through the destination node,if it can,the destination node will reply the CTS frame without its own MAC address,reducing the control overhead of4 bytes,if not,the destination node will reply TNR frame,canceling the interaction process between CTS and ACK frame.Secondly,an adaptive frequency-division multiplexing mechanism is proposed to solve the problem that the THZ beam of the destination node cannot cover the two source nodes,which leads to low throughput.The theoretical analysis and simulation results show that the proposed LE-MAC protocol has obvious advantages in MAC layer throughput,control overhead and other performance.Finally,the thesis summarizes the whole work,and briefly expounds the shortcomings of the current work and the next research work.