Study On Routing And Topology Control Techniques In Mobile Ad Hoc Networks

The mobile Ad Hoc network is a wireless system without a fixed (wired or wireless) infrastructure. It is a self-organizing network composed of mobile nodes or users. For two nodes not in mutual transmission range to communicate, their messages need to be relayed through a series of intermediate nodes. With mobility of the nodes, how to find the route to destination and optimize the network topology, improve the network performance, enhance the network survivability had became the key issues of research in mobile Ad Hoc networks.Starting from the intensely active area of research in mobile Ad Hoc networks, the issues about the routing topologies and topology control technologies are studied in this thesis. The main research works and results are listed as follows.1. A new geographic routing protocol GLNFR (Greedy and Local Neighbor Face Routing) was proposed in this paper, the topology of the network was planarized by the GG (Gabriel Graph). Every node stores only the location information of its immediate neighbor nodes and its local face information for forwarding the packets. With the increasing numbers of nodes in the networks, and increasing mobility rate, our simulations show that GLNFR achieves significantly better routing performance than others by storing a mount of additional state at each node.2. Based on the characteristics of mobile Ad Hoc networks, a new routing protocol PAGPSR(Power-Aware Greedy Perimeter Stateless Routing), which combined the Load-Balanced and Power-Aware algorithms based on GPSR (Greedy and Perimeter Stateless Routing ) and changed the forwarding strategy, was proposed in this thesis. The object of our routing protocol is to balance the consumption of energy of nodes and prolong the surviving time of the Ad Hoc networks.3. In mobile Ad Hoc networks, geographical routing protocol was a kind of important routing protocols, which requires the underlying topology be planar, sparse, connected and t-spanner in order to guarantee the delivery of message and bound the routing length. A new topology control algorithm named ODT (Optimal Delaunay Triangulation), which constructed the geometry structure named ODT graph, was proposed. Theoretic analysis showed that the ODT graph satisfies those properties, and our algorithms are much more communication efficient than previous algorithms which construct planar t-spanner of the original topology. These conclusions are confirmed by simulation results.4. A distributed topology control algorithm named for mobile Ad Hoc networks with directional antennas was proposed in this thesis. The topology is controlled not only by adjusting the transmission powers of nodes but also by changing the antenna's pattern (direction(s)). A node grows its transmission power until it finds some neighbor nodes in every sector of its directional antenna. The resulting network topology increases network lifetime by reducing transmission power and decreases traffic interference by having low node degrees. Simulation results demonstrate the effectiveness of the proposed algorithm.