Geographic Routing Algorithms In Maritime Wireless Mesh Networks

As an extension of the Mobile Ad Hoc Network(MANET)in the maritime filed,Maritime Wireless Mesh Network(MWMN)has a strong networking and self-healing capabilities.It can overcome the shortcomings of the traditional maritime communication systems,and provide a novel technical means and developing chance,which has drawn great attention from the industry.The routing algorithm is the key issue to ensure the fast and reliable transmission of maritime data in MWMN.Due to the variability and complexity of the maritime communication environment,the traditional MANET routing algorithms are incapable of being directly applied in maritime environment.Therefore,the routing algorithms have always been the one of the research hotspots in MWMN.In this paper,we first analyze the research status and key issues in MWMN,and then make a summary and analysis about the typical routing algorithms in MWMN.Secondly,focusing on the dense maritime network environment,we propose a Link Lifetime and Quality based Location Routing(LLQLR)algorithm,with a joint consideration of the influence of the ship motion characteristics and sea level condition.The LLQLR algorithm estimates the ship position by means of the Kalman filter prediction mechanism.On this basis,the proposal calculates the link lifetime factor and link quality factor between adjacent ship nodes,and proposes the concept of Weighted Forwarding Metric(WFM)by considering the above two factors.Accordingly,the ship with maximum value of WFM is selected as the packet forwarder.In addition,focusing on the sparse maritime network environment,we propose an Improved Nearest Point based Location Routing(INPLR)algorithm,with a joint consideration of the destination's movement state and the influence of variable sea surface condition.The INPLR algorithm first estimates the movement range of the mobile destination,and derives the calculation method of packet delivery time with the help of the nearest point.Then the proposal proposes the concept of carrying and forwarding metric based on the packer delivery time and sea state factor,and selects the ship with minimum value of carrying and forwarding metric as the packet carrier.Moreover,taking into account the defects of single-copy strategy and multi-copy strategy,the algorithm also designs a retransmission mechanism to reduce the number of the redundant packets and the number of packets dropped.Finally,we develop a MWMN simulation platform by means of the OPNET network software,and evaluate the performance of LLQLR and INPLR algorithm.The simulation results show that LLQLR algorithm has higher packet delivery ratio and lower average packet delay variation,while INPLR algorithm has higher packet delivery ratio and lower network overhead,compared with the comparison algorithms.