LAUSR

The incorporation of the cognitive radio (CR) technology as a spectrum management tool in satellite communication has attracted considerable research attention because the CR allows the coexistence of the primary and secondary networks using the same resources. In this paper, satellites and their users are considered as a primary network, and the terrestrial base stations (BSs) and their users are considered as a secondary network. Besides, it is considered that terrestrial users cause interference to satellite users due to technical and environmental constraints. This interference reduces satellite users’ satisfaction with downloads rate. In such a cognitive satellite network environment, content placement may also cause a decrease in user satisfaction. The successful download probability (SDP) is analyzed in this work based on different terrestrial user density. To utilize the satellite cache resources effectively, we propose two transmission strategies based on the terrestrial user density, namely, the multi-point cooperative transmission strategy (CT) and the parallel transmission strategy (PT). In addition, based on the cache service probability we determine the ratio of content distribution most popular content (MPC) and general popular content (GPC) and optimize the content placement process using the utility function in CT mode. Through computer simulation, we give numerical results of our method. The obtained numerical results show that the proposed strategies are effective in content placement.