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University: University of Wollongong, Australia Professor: Dr. Raad Raad Department: School of Electrical, Computer and Telecommunications Engineering High Performance Mobile Ad Hoc Networks with Directional Antennas Wireless ad hoc networks have become increasingly popular in recent years with the development of mobile devices such as laptops, cell phones and PDAs. There are several characteristics that make it difficult to build a high performance wireless ad hoc network. Firstly, the radio channel is a multi-access broadcast medium. Interferences between adjacent nodes are fierce, and MAC protocols are needed to solve the contentions and avoid collisions. Secondly, each node in ad hoc networks is self-configuring without any pre-existing central controllers. Multihop packet forwarding is needed when the destination is beyond one hop transmission range from the source node. As a result, each node in the network has burdens to relay other nodes’ traffic. Finally, power and bandwidth are valuable resources in MANETs (Mobile Ad-hoc Networks). Power control is preferred to prolong the battery life. The application of MANETs can be found in disaster relief, military operation and campus. Traditional MANETs are equipped with omni-directional antennas. Directional antennas make it possible to dramatically increase the performance of an ad hoc network. Directional antennas can focus most of their energy in one direction. As a result, they can achieve a longer transmission range and higher spatial reuse compared to omni-directional antennas. There are also new challenges to using directional antennas, such as the deafness problem and the new hidden node problem. This project aims to highlight the benefits of using directional antennas in ad hoc networks and suggest novel research areas for further study. Since directional antennas have such advantages that could dramatically increase the performance of MANETs. Researchers have done intensive study on both MAC and routing protocols for directional antennas. However the performance of MANETs using directional antennas is still far from optimum. We are using OPNET modeller to investigate current MAC and routing protocols for directional antennas and hoping to provide new and innovative solutions to this problem. |
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