Cross-Layer Routing Protocols For Maritime Wireless Mesh Networks

Maritime Wireless Mesh Network(MWMN)is a Mobile Ad Hoc Network(MANET)that consists of multi-hop ships,lighthouses and buoys equipped with wireless communication interfaces.MWMN has many advantages,such as rapid deployment,convenient maintenance,high scalability and so on.It can overcome the shortcomings of the traditional maritime communication system and provide convenient and fast broadband access services for maritime users.Routing protocol is very important to ensure the fast and reliable transmission of data packets in MWMN,which has attracted increasing attention in recent years.In this thesis,we first introduce the background,network characteristics and research status of MWMN.And then,we investigate the application in MWMN for some typical routing protocols of MANET and some typical routing protocols designed for MWMN recently.The main ideas of these typical protocols are described,and their characteristics are summarized and compared.Secondly,a Q-Learning based Adaptive Routing(QLAR)protocol is proposed forMWMN with the complex and variable communication environment and the poor link stability.With an integrated consideration of the characteristics of marine radio propagation,ship voyage information and meteorological information of corresponding sea area,the protocol proposes the concepts of link reliability,link stability and ship voyage similarity,and evaluates the link status.Moreover,according to the link status,the Q-Learning algorithm is used to look for the most stable path between the source and destination nodes for the transmission of data packets.This protocol can improve the packet delivery ratio,reduce average packet delay and normalized routing overhead.In addition,a Load-Balancing Cross-Layer Routing(LBCLR)protocol is proposed for MWMN with the problem of unbalanced load and congestion of ship nodes.With an integrated consideration of the cache queue occupancy of ship nodes and data packet forwarding of neighbor ship nodes,the protocol proposes the concepts of cache queue occupancy and wireless channel occupancy of ship nodes,and evaluates the load status of ship nodes.Moreover,according to the load status it predicts the congestion of cache queue of nodes to adopt different RREQ processing strategies.Furthermore,it uses the ship load factor and the sea state factor of ship as the routing criteria to establish a load balancing path between the source and destination nodes for packet transmissions.A route maintenance mechanism is also designed to predict the degree of node congestion according to the load of the node,and it use different strategies to dynamically update the route in network to prevent individual nodes from congestion during data transmission.The protocol is useful to balance the network load,improve the packet delivery ratio,and reduce average packet delay.Finally,we develop a MWMN simulation platform based on OPNET network simulation software to evaluate the performance of the two proposed protocols and compare them with several typical protocols in the literature.The simulation results verify the effectiveness of the proposals.