Overlapped-Coverage Satellite Communication System Design for Random Access Scenario

In this paper, a novel protocol is proposed to improve the performance of contention resolution diversity slotted ALOHA (CRDSA) protocol, which is called spatial coupled CRDSA (SC-CRDSA). Note that the coverage area of two satellites is partially overlapped. With the help of users which are located in the overlapped area, the received information from two satellites can be recovered together. Thus, the information from two satellites are coupled with each other. Then, we investigate the relationship between the overlapped area and the throughput performance. To evaluate the optimal ratio of the overlapped area, density evolution algorihm is used, which can guide the satellite constellation design. Simulation results prove that SC-CRDSA protocol achieves better performance than traditional CRDSA protocol.