Design Of Self-Adaptive Gateway In AODV Routing Protocol

With the rapid development of wireless communication technology, the coverage of MANET's (Mobile Ad Hoc Network) application has been extended widely. The independent researches of MANET technology can't meet the connection requirements between mobile wireless devices and the Internet. In recent years, the research of connections between MANET and the Internet has become an important research issue of MANET technology. And the key technology of connections between MANET and the Internet is the design of the connection gateway and the algorithms which can improve its performances according to the characteristic of MANET network.The connection gateway is the bridge which connects MANET with the Internet. It supports both the layered routing protocols of the Internet and multi-hop routing protocols of MANET, so it can implement the exchange of routing information between MANET and the Internet. And the connection gateway of MANET and the Internet supports two different network architectures by installing both wired network interface and wireless network interface. The connection gateway transforms the Internet routing protocols and MANET routing protocols to each other by implementing the packets re-encapsulation and forwarding. Connection gateway shields the protocols switching and packets encapsulating process to both the wired nodes and the wireless nodes, so the differences between the Internet and MANET is transparent to both sides.The thesis has introduced and analyzed recent representative research of connection gateway, and implemented the design of MANET connection gateway based on the AODV routing protocol. To satisfy MANET's dynamic topology, some improvements have been made to the connection gateway. The improved connection gateway reduces the control packet overhead which is caused by the connection gateway advertisements'broadcasting and forwarding. The methods used in the improvement are connection gateway advertisements' TTL self-adaptive and interval self-adaptive. The quality of service of connection gateway is improved. In addition, the end-to-end delay and forward rate of packets delivery are optimized in MANET and the Internet connecting environment. And micro-movement management algorithm is employed in the design so that the connections between MANET nodes and the Internet can work consequently and steadily when the nodes of MANET performing random movements. And by employing the micro-movement management algorithm, the improved AODV routing protocol can shield the unnecessary frequently switches among the gateways, so that the control packet overhead can be depressed effectively. The designed connection gateway, self-adaptive algorithms and micro-movement management algorithm in this thesis are developed on the NS2 network simulation platform.The performance of the designed connection gateway has been evaluated by analyzing the simulation results, comparisons have been made with the other connection gateways. The comparisons show that:the self-adaptive algorithms can suppress control packets overhead in connecting network environment, and the end-to-end delay of the system is improved. After employing the micro-movement management algorithm, the designed connection gateway can obviously reduce the total communication cost comparing to the other connection gateways, and the quality of service under the connection environment is improved.