Research On Key Technologies Of Laser Communication Networking

In recent years,research on laser communication technology at home and abroad has become increasingly hot.In order to solve the problem of weak anti-interference ability and low communication rate between nodes in the Ad hoc network,the laser communication technology is introduced into the Ad hoc network.Laser communication Ad hoc networks are an extension of wireless Ad hoc networks.The introduction of laser communication technology can overcome the electromagnetic interference problem,low rate problem and low confidentiality problem in the field of military wireless communication.However,due to the short wavelength of the laser,the small divergence angle,and one laser transceiver can only be in communication with another one,which brings challenges to the networking in the Ad hoc network.Solving the problem of laser communication networking between nodes is very important and meaningful for applying laser communication technology in Ad hoc networks.This paper mainly studies the problem of laser chain building networking between mobile nodes in free space.Innovatively proposed the laser chain-building algorithm and the laser chain-building protocol for free-space node in ad hoc networks.The laser chainbuilding algorithm is a heuristic algorithm based on set partitioning.The set partitioning operation can improve the performance of the algorithm when the connection between the nodes is not good,the heuristic function in the algorithm enables the algorithm to progress in the direction of the optimal solution.The laser chain-building algorithm calculates the connectable relationship between nodes according to the longitude,latitude,altitude and flight direction of nodes in free space.Based on the known connection relationships of all nodes,the laser chain building algorithm can complete the calculation of the full connection topology between nodes to achieve network layer communication between global nodes.The laser chain-building algorithm provides the function of link topology repair through the merge operation of the set,when the laser link is disconnected,communication between global nodes may be affected.The laser chain-building algorithm can determine the impact of the broken link on the communication between nodes when the link is disconnected,and maintain the topology to restore communication between the nodes.In addition,the laser chain-building algorithm has topology optimization capabilities to optimize network diameter and improve network performance.Based on the laser chain-building algorithm,this paper proposes a laser chain-building protocol.The laser chain-building protocol works at the data link layer to serve the network layer.The protocol includes seven control packets and one data packet.The control packet is responsible for establishing and maintaining the laser link between the nodes,and the data packet is responsible for forwarding the upper layer service.Different from the other six types of messages,which use the omnidirectional antenna for transmission,the link heartbeat message is sent and received by the laser transceiver.The link heartbeat packet is used to periodically detect the status of the laser link.The laser chain-building protocol was modeled and simulated on the OPNET network simulation software.A large number of simulation results show that the laser chain-building algorithm can complete the calculation of the laser link topology in any scene.The laser chain-building protocol can complete the data message forwarding in any scene.