Research On Routing Algorithm In Underwater Wireless Optical Communication Sensor Networks

With the development of wireless communication technology,wireless sensor network technology and relay cooperative transmission technology have received extensive attention.The increasing demand for marine resources has prompted the development of underwater wireless communication technology.Underwater wireless optical communication sensor network has the advantages of high speed,low delay,and low equipment cost.Due to the physical characteristics of optical communication and the complicated underwater environment,underwater turbulence will affect the line-of-sight transmission of optical communication.Alignment problems between nodes often occur,and it will resulting in the link failure between the nodesIn order to repair the problem of link failures between nodes,this thesis uses relay cooperative transmission to repair the connectivity of the link.Besides,the work started from two aspects: fixed relay and mobile relay.The link repair of the underwater wireless optical communication sensor network can ensure the connection between nodes.Relevant research was conducted on wireless sensor network technology and relay cooperative transmission technology.The network structure,characteristics and application scenarios of wireless sensor networks are introduced,and cooperative communication and relay selection scheme are discussed.Aiming at the problem of link failure,a relay selection algorithm based on the mixture EGG model is proposed.Firstly,the link failure node selects the relay node according to the BER,use the nodes which meet the BER conditions as the candidate relay set.Then,select the node which has least energy consumption,the set of candidate relays according to TTP,then we put this node as the relay.Simulation results shows that the algorithm proposed is better than random relay selection in terms of computing time and network lifecycle.On the base of the relay selection algorithm,this thesis carried out the research of mobile relay cooperative transmission algorithm,this algorithm can solve the problem of link failure caused by turbulence in underwater wireless optical communication.And propose a relay selection algorithm based on mobile node.The algorithm under the premise of ensuring the normal communication between the mobile relay and the link failure node,with the goal of minimizing the energy consumption of the mobile relay,plan the movement path of the mobile relay.The mobile relay node communicates with the link failure node at the geometric center and the connectivity between nodes is judged by BER.If there are still unconnected nodes,the mobile relay node will move to the allowed communication range for relay cooperative communication.Simulation results shows that when the number of link failure nodes in the system increased,this algorithm can effectively reduce the energy consumption of mobile relay node and improve the system BER performance.