Design And Implementation Of Time Division Multiple Access Protocol In Ad Hoc Networks

Mobile Ad Hoc Networks(MANET)do not need fixed infrastructures,they are distributed and self-organization,which are convenient for the rapid construction of the network.MANET network topology can be arbitrarily changed,which makes it very suitable for battlefield,rescue and other special environment,the application is also very extensive.Due to the broadcast characteristic of wireless channel and distributed control features of network,multiple access(MAC)protocol becomes the core technology that affect network performance.The dynamic time slot allocation based TDMA protocol has been popular in MANET research because of its advantages of adapting to topology changes and supporting Qo S.The keys in the design of distributed TDMA protocol are reasonably allocating the time slots without conflicts and ensuring the nodes get enough time slots quickly as the business demand increases,so that it can adapt to different business needs,such as mixed or bursty traffic.For specific applications,a TDMA protocol based on fixed and dynamic slot allocation is presented in this paper.Firstly,the frames of the protocol and the fixed slot allocation algorithm without collision in two hops are introduced.Secondly,the process of joining and exiting network,the states of the nodes in the network and the relationship between these states are described.Thirdly,the algorithm of dynamic slot reservation and release is introduced in detail.Kalman filter algorithm is used to monitor and predict the length of data queue in MAC protocol,it can quickly determine whether the current service rate of the node meets the needs of the business rate,that is,whether the node satisfies the open condition of dynamic slot reservation and release.At the same time,a three-step handshake process is designed for negotiation of time slot reservation and release among nodes.Once the node satisfies the condition of slot reservation and release,the three-step handshake process is performed to quickly acquire or release time slots to meet the needs of the business.Finally,the software implementation based on C language is introduced.The Linux system is taken as the software running environment.In this environment,the test software is used to simulate the MAC protocol implemented in this paper.The simulation results show that the MAC protocol can realize the network connection and disconnection process of multiple nodes.Through the real-time monitoring and accurate prediction of the data queue length,the node can response quickly to the change of traffic in the network,and make a reservation or release time slot in a short time.Not only meet the needs of different business,but also improve the utilization of time slots.Finally,the correctness and validity of this protocol are verified on the actual hardware communication platform.