| With the explosive growth of modern multimedia information,the traditional terrestrial network has been unable to meet the growing communication needs of mankind.Building a world-wide integrated information network combining space-based networks,space-based networks,terrestrial broadband networks and mobile communication systems will be an effective way to enhance China's overall communication capabilities.Considering the large-capacity and high-rate characteristics of space-based networks,it is especially important to construct a flexible and efficient satellite communication system through space networking technology.In order to support the transparent forwarding and high-speed transmission requirements of multiple services in space,this thesis conducts in-depth research on spatial optical burst switching networks.The specific work contents and research results are as follows:A centralized resource scheduling mechanism with traffic adaptation function is designed based on single-wavelength channel.Because the cache capacity of the space backbone node is limited,the master node dynamically adjusts the bandwidth of the sub-wavelength level to manage the network traffic,which effectively reduces the average packet loss rate of the entire network.Secondly,a corresponding solution is given for the problem that there is a certain offset time between the control information and the corresponding data.The system reduces the possibility of resource conflicts by adjusting the transmission time of the service at the source node,and realizes the non-blocking exchange of burst data packets.Based on the centralized resource scheduling mechanism,a spatial dynamic bandwidth allocation algorithm supporting multiple services is designed.First,the corresponding solution is given for the "cross-master node"conflict problem.Secondly,a dynamic bandwidth clipping algorithm based on the priority principle and a time slot mapping algorithm based on the principle of sequential configuration are designed.The algorithm implements conflict-free switching of network data packets,so that the system can respond to sudden service demands more quickly,and further improve the bandwidth utilization of the space optical switching network.Based on OPNET Modeler,a spatial optical burst switching network simulation platform for multi-service is built.First,based on the centralized resource scheduling mechanism,the simulation platform focuses on the impact of system key parameters such as GEO cache capacity,frame length,and DBA cycle on network performance.The simulation platform verifies the rationality of the spatial optical burst switching network resource scheduling mechanism and the feasibility of the dynamic bandwidth allocation algorithm.The simulation results show that the DBA algorithm based on the priority principle can preempt the bandwidth resources for high-priority services,that is,it can meet the priority transmission requirements of high-priority services for multiple services,and improve the comprehensive processing capability of the system. |
