Design And Implementation Of MAC Protocol For Maritime Broadband Wireless Ad Hoc Network

With the rapid development of China's marine industry,maritime broadband communication is becoming more and more important in civil communications,military communications and maritime emergency communications.However,the traditional maritime communication can not meet the needs of the current maritime communication services.In addition,the marine channel resources are limited.How to allocate the channel resources reasonably is a problem that needs to be solved in the current maritime broadband communication.Media Access Control(MAC)protocol is a mechanism used to decide how to allocate limited channel resources correctly for transmission nodes.There are many MAC protocols based on wireless ad hoc networks at present.However,considering the complexity of maritime communication environment,it is important to design a MAC protocol that can be applied to maritime broadband wireless ad hoc networks to meet the needs of different maritime communication services.Significance.Firstly,this thesis studies and analyses the current network architecture and development status of the offshore broadband communication network,studies the media access control protocols commonly used in wireless ad hoc networks,and simulates the performance of the commonly used MAC protocols by using NS2(Network Simulator version 2)simulation software.Through detailed comparative analysis,the IEEE 802.11 MAC protocol is chosen as the basis for the implementation of the MAC protocol in the maritime broadband wireless communication network.The MAC protocol is divided into several core modules according to its functions.Using POSIX-compliant multi-threaded programming technology under Linux operating system,the core function modules of media access control protocols,such as frame sending,frame receiving,conflict avoidance,channel state detection,as well as buffer management and protocol interface,are compiled to implement a complete MANET media access control protocol.On this basis,a broadband MANET experimental system is constructed by using wireless ad hoc network communication nodes.By designing different network topologies,the designed media access control protocol is experimentally studied,and the performance of the media access control protocol in single-hop network environment and multi-hop network environment is verified.Through experiments,the delivery rate and throughput of the media access control protocol are obtained.The stability of the protocol and the multi-hop transmission performance under the distributed structure are verified.The experimental results show that the designed MAC protocol can meet the needs of multimedia data transmission in the marine broadband communication network.