Research On Routing Protocols Based On Ad Hoc Access Networks

With the development of mobile communication technology, Ad Hoc access network has become one research focus Ad Hoc access network can extend the transmitting range of the communication system, balance the service of neighbor cell and promote the data rates of the range of the cell via the multi-hop capability of the Ad Hoc nodes. The nodes in the Ad Hoc networks communicate with the correspondents in the internet through the gateways. As a result, the key points of the Ad Hoc access focus on the gateway discovery and the selection and handoffs between different gateways.The traditional gateway selection algorithms select the gateway with the standard of hops or network overload, which has the defect of frequent handoffs or more hops. Two improved algorithm are proposed based on the average access time and the route stability respectively. What's more, since the hop is one important factor which will affect the network performance, it is also considered in both improved algorithms.The improved algorithm based on access time adopts the idea that more access time will improve the communication continuity. The improved algorithm which adopts route stability is based on the thinking that the more stable route will bring less lost packet and more stable communication between Ad Hoc nodes and the gateway. In addition, the adoption of more parameters to choose the gateway overcomes the defect of Jelger algorithm: frequent handoffs and more hops. The simulation results prove that the improved algorithms can promote the performance of the communication.The thesis also compares and analyzes the performance of the main types of routing protocols in Ad Hoc networks in detail: On-demand routing protocols and Table Driven protocols.