Ad Hoc Networks, A Tdma-based Mac Protocol Comparison

The Ad Hoc network is composed of a collection of mobile nodes, which are connected together by their wireless links. In this environment, mobile nodes may function as communication terminals or intermediate nodes (routers). One distinguishing feature is that users, when communicating to each other, may establish a multi-hop path among these wireless links, quite different current existing networks, another distinguishing feature is that the network topology in Ad Hoc networks may be frequently changed and dynamically adapted. Due to their high flexibility and high survival ability, Ad Hoc networks are very much suitable for the use in battlefield communications; nonetheless, more and more civil communications such as rescue operations and city bus communication are adopting Ad Hoc networks in recent years.It is known that media access control (MAC) plays an important role on link utilization and fairness issue, particularly in wireless Ad Hoc networks, MAC mechanisms would become more complicated because of hidden-terminal and exposed-terminal occurrence and frequency changes of network topology. These open problems motivated us to conduct a comprehensive study in this dissertation.Some research about the MAC protocols based on TDMA and analyzed the schedule solutions of them was make in the paper. These protocols include three classes: fixed allocation, dynamically allocation and hybride (combines an allocation and contention) allocation. I choose three protocols from them and make some simulations in different environment for these protocols based on OPNET, and make some summaries which will be useful for networking in the real environment. We proposal a solution for the real-time traffic based on the AGENT protocol for the Ad Hoc network's requirements of QoS. The performance of the proposed protocol is analyzed, and the simulation results show that the performance is achieved better than the original. The result will be useful for the research about the difference service in the MAC protocol.