Abstract:

Firstly, considering a reconfigurable intelligent surface (RIS) assisted satellite terrestrial integrated network, the satellite employed the rate splitting multiple access technique to serve multiple earth stations in the presence of multiple eavers-droppers(Eves), while the terrestrial network leveraged multicast technique to serve many ground users with the assist of RIS.Secondly, assuming that only the Eves’ imperfect channel state information could be obtained, a joint optimization problem was formulated to minimize the total transmit power, while ensuring the quality-of-service requirement for all users, and adhering to intercept probabilistic constraints.To tackle this noncom vex problem, the S-procedure and the successive convex approximation approach were employed to convert the intercept probabilistic constraints into solved ones.And then a nuclear norm-based penalty function was employed to propose a robust joint algorithm to obtain the robust beamforming weight vectors and transmit power.Finally, the simulation results demonstrate the effectiveness and superiority of the proposed transmission scheme.

Key words: satellite terrestrial integrated network, reconfigurable intelligent surface, rate splitting multiple access, robust beamforming, intercept probability constraint