The Theory And Implementation Of The MAC Protocols For Underwater Acoustic Network

As a part of the land,sea,empty stereo network,underwater acoustic communication network plays an important role.Now research and application of underwater acoustic communication network in our country is still in the initial stage.Considered from the underwater acoustic communication network to achieve efficiency,large scale field test efficiency and test cost,it is urgent to build an efficient,flexible and controllable software system which can study on Simulation,Emulation and field experiment.And then on this basis it study on the control protocol of MAC layer.This article is just based on this demand to carry out the related research.Firstly,this article build the development environment for network simulation and experiment for which include the main job: the analysis of frame structure of NS2 and its extended software,the analysis of Simulation and the operation mechanism of NS2 network software.Describes two auxiliary processing tool,which lays the foundation for the further research and development of underwater acoustic communication network.Secondly,according to the application demand,this article research focus on the theory of ALOHA and CSMA/CA two MAC layer protocol.Basing on the built of underwater acoustic communication network development environment to simulate the two based MAC protocol,this article through the analysis of the simulation results.It presents the relationship of the packet length with network throughput,end to end delay and the packet loss rate.This result provides important reference basis for selecting the packet length for Outfield real system drop test.Thirdly,the height of the reuse of code for Simulation,Emulation and outfield experiment,at the same time improve the outfield experimental flexibility and high performance price ratio,this article achieve the following works:(1)Developing a general interface which is based on OMAP-L138 platform.This interface include to parts: a driver between DSP and ARM core and a program called multiplex layer.It is responsible for the exchange of information between the NS2 software and Physic layer.Because of this interface,the development of NS2 software and physic layer are independent for each other.(2)Implementation of a control link mechanism,this mechanism avoids inconvenience frequent replacement protocol.It achieves the functions as follow: 1)It monitors and records of each communication node working state.2)It can remotely control the communication start,stop and replace protocol at specific time.Finally,this article use the integrated software system and physic layer to complete the field test of underwater acoustic communication network.The MAC layer test network using the ALOHA protocol.Tests prove that the integrated system is stable.This system can realize monitoring and control of the state of the node communication network and simply achieve to start,stop and replace protocol at specific time.It greatly improve the test efficiency,and reduce the consumption of manpower and material resources test.After all,this article statistics network performance test which MAC layer use the ALOHA protocol.The result achieve the desired effect.