The Design And Simulation Of MAC Protocols In Data Link Networks

The data link network,which is an application of wireless network in the military field,combining the characteristics of wireless networks and military scenario,has made great contributions to the enhancement of the operational capacity of the army.However,the gradually increasing battlefield scale and complicated electromagnetic environment of the modern warfare have brought some challenges to the development of data link networks,which means they are currently facing some problems.For example,it cannot fully utilize limited resources and provide the corresponding service quality guarantee for different businesses.Besides,the fixed channel access mode in MAC layer cannot flexibly switch the working channel to effectively solve the enemy's deliberate interference.Moreover,the data link network cannot adapt to the changing topology binging by the high-speed mobile terminals.This paper focuses on the research of MAC protocols in data link networks,including the polling protocol based on Link11 and the TDMA protocol based on Link16,in order to design reasonable and efficient MAC protocols to solve the above problems by introducing the related technology of cognitive radio.Firstly,after studying the research status of MAC protocols in the polling network and the TDMA network,this paper analyzes the shortcomings of existing MAC protocols based on the requirements originating from actual battlefield environment.Moreover,this paper proposes that the cognitive radio technology can be used to solve the above problems.Secondly,this paper discusses the overall goal of designing the enhanced MAC protocols,which combines the MAC protocols in data link networks and the cognitive radio technology,and then deeply analyzes the difficulties involved in the design process.Based on the above contents,this paper designs the protocol stacks of the network's nodes and the access strategy as the first step,and then,this paper proposes an enhanced MAC protocol for polling networks and another one for TDMA networks,starting from the design of MAC layer's overall slot structure,to the design of three detailed functions: resource allocation,channel management and dynamic joining or exiting scheme of networks.The innovation of the above MAC protocols mainly lies in three aspects.Firstly,there are two optimization schemes for the resource allocation policy,one is the dynamic polling strategy for the polling network and another one is the dynamic time slot allocation algorithm for the TDMA network.Both of the two schemes can improve resourceutilization while providing different time delay guarantees for different businesses.Secondly,the MAC protocols mentioned above improve the anti-jamming performance of data link networks by introducing the technology of spectrum sensing and channel management.Thirdly,this paper designs two different schemes of dynamic joining and exiting networks for polling and TDMA networks according to their characteristics and overall time frame structures,which provides a guarantee for the mobile terminals accessing the heterogeneous networks dynamically.Finally,this paper designs and develops the specific node models and process models in the data link networks by using the OPNET simulation platform,leading to the successful building of the simulation models of the high-speed mobile node,polling network and TDMA network,and then the proposed MAC protocols are tested.The test results show that the MAC protocols proposed by this paper can achieve the expected function and performance requirements,which means the feasibility to a certain extent.