Research On Channel Reservation Based Distributed Multi-channel MAC Protocol

With the continuous development and evolution of the distributed wireless networks,a large number of users may have requests to access to wireless networks at any time.In order to make full use of channel resources of the networks,multi-channel medium access technologies have become one of the current research focuses.In the distributed wireless networks,the channel access method based on random competition has been accepted and widely used by both of the industry and academia fields.However,due to the reasons including the densely deployment of wireless nodes,low energy requirements as well as the fading effects of wireless channel,severe challenges are brought on the multi-channel MAC design,including channel access efficiency,resource utilization and network throughput.In the face of the problems above,in this thesis,we integrate channel reservation with the design of multi-channel multiple access protocol,so that the advantages of channel reservation can be fully exploited,which makes this work more targeted.The main innovation points of this thesis are as follows:1.A distributed multi-channel MAC protocol based on channel reservation is designed,which can solve the bottleneck problem on the common control channel,the highhardware complexity and power consumption of system are reduced as well.By using channel reservation,multiple transmission opportunities can be reserved in advance on the selected data channels by only performing a successful control handshake on the control channel,thereby the congestion on the control channel can be reduced and the bottleneck problem on the control channel is effectively alleviated.Simulation results show that by using channel reservation,the network throughput,average packet delay and utilization of the control channel can be significantly improved.2.A distributed multi-channel MAC protocol combined with cooperative relay and channel reservation is designed to improve the data transmission rate of deep fading channels.By constructing the RCL(Reserved Cooperative Link),the channel reservation and cooperative relay are combined and applied to the design of multi-channel MAC protocol.The simulation results show that under the deep fading channel,the network throughput and average packet delay can be significantly improved by combining the channel reservation and cooperative relay.3.In the next generation WLAN,a multi-channel multiple access method based on channel reservation is proposed,which improves the performance of the protocol.Aiming at the trigger frame(TF)unreliable transmission problem in the existing IEEE 802.11 ax channel access mechanism,the robustness of the trigger frame transmission is enhanced by using channel reservation,so as to improve the channel utilization.