SLNR-based Secure Energy Efficient Beamforming in Multibeam Satellite Systems

Motivated by the fact that both security and energy
efficiency are the fundamental requirements and design targets
of future satellite communications, this letter investigates secure
energy efficient beamforming in multibeam satellite systems, where
the satellite user in each beam is surrounded by an eavesdropper
attempting to intercept the confidential information. To simul-
taneously improve the transmission security and reduce power
consumption, our design objective is to maximize the system secrecy
energy efficiency (SEE) under the constraint of total transmit
power budget. Different from the existing schemes with high
complexity, we propose an alternating optimization scheme to
address the SEE problem by decomposing the original nonconvex
problem into subproblems. Specifically, we first utilize the signal-
to-leakage-plus-noise ratio (SLNR) metric to obtain closed-form
normalized beamforming weight vectors, while the successive convex
approximation (SCA) method is used to efficiently solve the power
allocation subproblem. Then, an iterative algorithm is proposed
to obtain the suboptimal solutions. Finally, simulation results are
provided to verify the superiority of the proposed scheme compared
to the benchmark schemes