Ultrashort Wave Channel Ad Hoc Network Data Link Layer Protocol

Ad Hoc network is a network system which is not depended on a fixed network infrastructure and can spread out rapidly. Because of its characteristics of flexibility in networking and completely distributed operations, Ad Hoc network is hardly restricted by environments, and its robustness is also very strong. As a result, Ad Hoc network is especially fit for applications such as tactical communication for military, disaster rescue, etc.In Ad Hoc Network, Due to its special form of organization, many protocols used in networks with pre-configured and centrally controlled infrastructure,cannot be directly applied to Mobile Ad Hoc Network. Thus protocols need to be carefully designed for this kind of network.Among them, designing a data link layer protocol which can provide good supportion to upper, is a main difficulty for MANET, and is also a key to determine the communication functions and the performance of the network. Furthermore, because of it's strong points of communication stably, VHF channels is used in tactical communications. So, combining the VHF channel with Mobile Ad Hoc Network is a focal point of this paper.First, we make a simply introduction and analyse of the American military communication systems and their technologies for data link layer.Second, combining the characteristics of the VHF channel and the transmission system, we analyse the medium access control protocol and use the MAC protocol which is based on TDMA. And then, we propose a Ad Hoc network data link layer protocol which is fit for the VHF channel: In this protocol, the protocol that the MAC layer uses is IFPRP. IFPRP is a improved protocol based on FPRP, and IFPRP can assure reliable broadcasting, at the same time, it also improves the throughput and decreases the network delay; The link layer protocol uses techniques of error controlling and piggyback transporting in LLC layer, as a result, it increases the reliability of data transmissing and decreases som spending.In this paper, Chapter 1 introduces the background and content of the study. Chapter 2 briefly introduces the American military communication systems and their technologies for data link layer. Chapter 3 combing the characteristics of the VHF channel and the transmission system, proposes a Ad Hoc network data link layer protocol which is fit for the VHF channel. Chapter 4 constructs the network simulation model by using OPNET. Chapter 5 analyses the result of the simulation, and the performances of this data link protocol behave feasible, so it can provide references for the design of VHF MANET data link protocol. Finally, Chapter 6 summarizes the work and proposes the improvements.