Study On Efficient Routing Protocols For Wireless Multi-Hop Networks

Design of efficient routing protocols for wireless multi-hop networks (including wireless Ad Hoc networks and wireless sensor networks) have attracted a lot of attention and much work has been carried out. A wireless multi-hop network is in general a distributed network system. In such a wireless network, end-to-end communications generally go through multiple hops, and each terminal acts as both router and host. A wireless multi-hop network is dynamically reconfigurable and self-organized without fixed infrastructure. Wireless multi-hop networks are characterized by dynamic topologies, bandwidth-constrained, variable capacity links, and energy constrained. These characteristics have posed great challenges in the design of efficient and scalable routing protocols for such wireless networks.In this thesis, we study the design and evaluation of efficient and scalable routing protocols for dynamic wireless multi-hop networks. The contributions of this thesis are as follow: 1. Destination-driven On-demand multicast Routing Protocol for Mobile Ad Hoc networks (D-ODMRP).The design objective of D-ODMRP is to improve the multicast forwarding efficiency. To achieve this goal, the path to reach a multicast destination is biased towards those paths passing through another multicast destination. If multiple such choices are available, the one leading to the least extra cost is selected. D-ODMRP embeds this destination-driven feature into the on-demand multicast structure building process of a popular multicast routing protocol ODMRP. Simulation results show that D-ODMRP can greatly improve the forwarding efficiency as compared with ODMRP. Moreover, the destination-driven design can also work well with other existing multicast routing protocols for wireless ad hoc networks, including both mesh-based and tree-based multicast routing protocols.2. Dynamic anchor-based voronoi routing protocol for mobile wireless sensor networks (AVRP). AVRP is designed for wireless sensor networks with one or more mobile data-collecting nodes (i.e., mobile sinks). This protocol employs dynamic Voronoi scoping to maintain the shortest path from each sensor node to the nearest sink. The protocol introduces selection of anchor nodes to absorb the small movement of sinks, while maintaining the good property of Voronoi scoping when creating forwarding structure. Furthermore, to further reduce the protocol overhead, the protocol introduces a relay node between an anchor and its associated sink, if possible, and direct reporting data to sinks by sinks' neighboring nodes. Simulation results demonstrate that AVRP can achieve significant reduction in the frequency of delivery structure refreshing, and reducing protocol overhead, while maintaining good packet forwarding efficiency and delivery ratio.3. Trail-based data gathering for mobile wireless sensor networks (TRAIL).TRAIL is aimed for wireless sensor networks with one or more mobile sinks with light traffic. TRAIL is a combination of random walk and trail-based packet forwarding. TRAIL has the following advantages. First, it is simple and has low protocol overhead. Second, it is fully localized in nature and light weighted. It contains trail creation, trail-based forwarding, gratuitous route learning, multi-trail-handling, and random walk. TRAIL is suitable for wireless sensor networks with single mobile sink or with multiple mobile sinks. Simulation results show that TRAIL has high packet forwarding performance, and can reduce control overhead greatly.4. Location-based energy-efficiency grid adaptive fidelity algorithm (E-GAF).E-GAF is designed to balance the network load, and to prolong the network lifetime. It works on top of an existing grid-based clustering algorithm. In E-GAF, the grid coordinate origin is dynamically changed to adjust the grid structure, as a result the forwarding tasks taken by nodes inside the network are balanced, and further energy consumption balancing is achieved over the entire network, and thus the network lifetime is prolonged. Simulation results show that E-GAF could significantly prolong the network lifetime, and have good data delivery performance compared with existing algorithm.