Secure Transmission in Multi-Beam Satellites

We study the potential of spatial modulation to enhance secrecy in multi-beam satellite communications with perfect channel knowledge at the transmitter. Different optimization criteria are proposed complemented with an adaptive scheme to improve information secrecy. Results show that an eavesdropper suffers from a high performance degradation while an optimal performance is guaranteed at the legitimate receiver. We also show that perfect secrecy of the spatial bits can be achieved in the sense that they cannot be recovered by the eavesdropper even with very high computational power.