Ad Hoc Network Multipath Olsr Routing Protocol Based On The Dynamic Link Congestion Degree

Mobile Ad Hoc Network (MANET) is a distributed multi-hop wireless network without pre-established infrastructure. There is no central controller. Each node is not only a host, but also a router. As it's flexible to communicate and easy to organize, MANET can be used for emergency rescue and relief work, temporary conference and military communications. For the present, routing protocol is a heated and difficult point in MANET research.After deliberating on many classic routing protocols for Ad Hoc network, mainly the OLSR protocol, an improved protocol based on OLSR, LCDDM-OLSR, is proposed. The protocol brings in link congestion degree (LCD for short) and combine it with multipath policy, which creates a link congestion degree based dynamic multipath policy and achieve congestion control in network layer. LCD is used to measure the load of a node or local area. Before transmitting data, check the LCD of the next hop and decide which strategy is better to use. This makes sure LCDDM-OLSR is load-adaptive. Bringing in multipath policy and transmitting data with multiple path at the same time can increase throughput, balance the load and decrease the end-to-end delay, especially in high traffic networks. The point of this paper is the LCD based dynamic multipath policy, which combines LCD and multipath. When there is a demand for sending a huge amount of data and the average LCD of the local area around the source node is not that large, the dynamic multipath strategy will be started and find multiple paths to the destination on-demand. This routing discovery will automatically filter out nodes with heavy load and get paths with low load. That the multipath policy is dynamically decided to be used or not will greatly reduce the route maintainance and updating cost of multipath policy for table-driven routing protocol, as the cost of improving network performance with multipath is to increase every node's cost. As the number of nodes increases, updating the route table even for one time will cost a lot with multipath policy. However, with dynamically decided multipath policy, the cost will be greatly cut.At last, an implementation of LCDDM-OLSR is made with VC6.0 developer tool and C++ programming language. Eventually the basic functions are realized. At the same time, the paper put forward a further research perspective.