Mobile Ad Hoc Network Olsr Routing Protocol Extensions

Mobile Ad hoc NETwork (MANET) is a wireless multi-hop network without pre-established infrastructure. There is no central controller and the MANET is completed distributed. Because of its convenience, quickness and robust, the MANET can be used for emergency, temporary communication and military requirement.The most mature research in the mobile ad hoc network is routing protocol. OLSR (Optimum link State Routing Protocol) is a standardized table-driven routing protocol. The Dijkstra algorithm of the least of hops is used for path calculated in OLSR. But the protocol only tries its best to transmit data, not considering the state of wireless link.Because of the disadvantage above, this paper has completed two improvements to the OLSR. The first is changing the single path in traditional OLSR protocol to multipath OLSR. The intention is to distribute the data on all nodes in the network as soon as possible. The multipath OLSR protocol will calculate all of possible paths from the source node to destination node. Then, it should select one of paths with less congestion nodes for the second path. The paper has designed an effective algorithm of load assigned, to avoid overwhelming some central nodes in the network. The second changing used bandwidth and delay as constraint in algorithm of calculating routing. The changing is mainly for QoS service in MANET. Because the traditional OLSR ignores the state of wireless link, it can not make use of the most resource of the MANET. Therefore, the constraint OLSR routing protocol is needed. And also, the paper adds the constraint OLSR to SWAN, a simple but available QoS model. The SWAN has two important measures to realize the QoS service, one is rate_controller for best-effort traffic, the other is admission_controller for real-time traffic.The paper has discussed the two changing on traditional OLSR protocol. And simulations of the two improvments on OPNET have been completed. In the situation of speed of mobility and data_send, the simulation compared the improved OLSR with tradional OLSR protocol. Throughout the result of simulation, multipath OLSR and constraint OLSR can get advance in suucess_rate or end_to_end delay.