Research Of Cooperative Transmission And Access Algorithm Technology In Air&Space Network

Air&Space network is a system that intelligently captures, transmits and processes information in real time based on aerospace carriers. This network possesses the ability of autonomous operation and management. The types of communication nodes, traffic load and transmission pattern is developing continuously in the direction of diversification. Under this overall background, the cooperative transmission mechanism and user access control becomes an important means of improving Air&Space network load balance and increasing transmission resource utilization.In this thesis, a cooperative transmission scenario is proposed, in which the traffic from source GEO (Geostationary Earth Orbit) satellite is shared by other GEOs through inter-GEO laser communication links when the source GEO is operating under high load. And the method used to split the traffic load is also presented. So the traffic rate limitation of single link transmission is broken through to solve the problems of restricted data rate and low reliability. Moreover, the channel utilization between GEO and LEO (Low Earth Orbit) satellite is improved in this scenario.Furthermore, the access selection method, choosing the closest GEO satellite based on received signal strength, of traditional satellite communication scenario can no longer satisfy the need of modern Air&Space information network. Access selection and multi-access mode should adapt to Air&Space circumstances and network condition. Hence, in this paper, an access selection and a "Fix/Reserve/Poll" time slot assignment, which is modified from traditional TDMA mechanism, are proposed according to Air&Space network. In the end, an Air&Space access simulation platform is put up based on OPNET simulation software to run and test the access selection and multi-access mechanism.