Research On Routing Protocols And Node Localization Algorithms For Underwater Acoustic Sensor Networks

As a special kind of wireless sensor networks, UASNs-Underwater Acoustic Sensor Networks offers a new way to explore the underwater world. UASNs has been attracted significant attention recently and can be widely used in many areas such as environmental monitoring and protection, resource exploration, assisted navigation, water economy, disaster relief, military applications etc. However, low-bandwidth of the underwater acoustic channel, multi-path effects, random changes in high latency, and high noise background and the Doppler Effect makes the high-performance UASNs become a worldwide problem. In addition, underwater sensor nodes have a beam width and three-dimensional random direction, which also had a great influence UASNs, and this is often ignored by investigators. Routing protocol and underwater node localization algorithm are fundamental issues for UASNs. They ensure high efficient communication of UASNs and has great impact on the performance of UASNs. Aiming to reduce network delay, improve the energy efficiency of the network and extend the lifetime of the network, we study the routing protocols and node localization algorithms for UASNs.We first do some research on the routing protocols for UASNs. Based on the sufficient investigation and research on the existing routing protocols, we analyze the impact on the underwater network which caused by the transmit signal beam width and three-dimensional direction of the underwater sensor nodes. We propose a link-state based adaptive feedback routing protocol for static water environment, the protocol takes into account the emergence of asymmetric links and the decline of the network connectivity caused by beam width and direction. Theprotocol ensures that the sensor nodes can effectively get their routing information when a large number of asymmetric links in the underwater network environment, and avoid the huge energy consumption caused by the periodic update of the routing table.We further proposes a beam width and direction concerned routing protocol for dynamic water environment.The protocol assuming that each node already know the location of itself and the sink node, and uses the beam width and direction of the underwater sensor nodes to complete the route optimization.The protocol can achieve relatively high packet delivery rate and reduce energy consumption inthe low network connectivity dynamic topology network. Protocol can effectively achieve network self-organization can be applied to multi-gateway networks.At last, this paper carries out some research on underwater node localization algorithm for some of the underwater routing protocols need to know the location information of the nodes. We achieve symmetric linkranging without time synchronization and solve the problem of asymmetric link ranging without time synchronization.The proposed localization algorithm can effectively improve the localization coverage, and can effectively improve the localization accuracy.