Research On A Low Transmission Delay Dynamic Timeslot Allocation Protocol In TDMA Manet

Mobile Ad Hoc Networks(MANETs)have the advantages of easy deployment,strong resistance to destruction,and high flexibility.Moreover,a TDMA-based MANET can provide higher throughput than contention based MAC protocols because of its conflict-free characteristic.Thus it is wildly used in many fields,such as military application,disaster rescue and space explosion.On the other hand,the distributed control scheme in a TDMA MANET also results in a contradiction between the dynamic allocation of time slots and the rapid wireless channel access time of burst frames.To achieve the time slots allocation on demand,a lot of protocol overhead is required.Therefore,how to design an efficient method for time slot allocation and schedule that can respond quickly to burst data with less overhead,becomes the key point of the research of the MAC protocol in self-organizing networks.In order to shorten frame access delay and promote network throughput,a hybrid slot assignment and schedule protocol — BTSA is presented in this thesis.The protocol combines reservation-based schedule and contention-based schedule,and allocates time slots in both node activation and link activation manners.In this protocol,priority broadcast slots are used for low rate broadcast traffic,such as route information.Resource negotiation mini-slots are used for efficient slot negotiation and reservation to support normal rate traffic.The time slot lock scheme can handle high rate stream traffic by fast access to wireless channel.So BTSA can guarantee the service quality of multiple kinds of traffic in MANET.To verify the correctness and performance of the BTSA protocol,it is modeled and simulated on the OPNET simulation platform and compared with the USAP protocol and the dynamic TDMA protocol with the performance targets of network throughput and average frame access delay.Simulation results show that BTSA has better performance than USAP protocol and dynamic TDMA protocol in network throughput and average frame access delay on various topologies and has better adaptation in mobile scene.