A Novel Cooperative Physical Layer Security Scheme for Satellite Downlinks?

摘要

A physical layer security scheme based on cooperative relays is proposed to address the problem of eavesdropping in satellite downlink which is induced by the broadcasting nature of the shared communication medium and the long distance of the satellite-ground transmissions. By evaluating the outage probability, the relay nodes par-ticipating in cooperative communication can be divided into a cooperative forwarding group and a cooperative jam-ming group. The cooperative jamming group and the co-operative forwarding groups construct a cascaded channel which combined with the random weighting technique im-proves the quality of transmission on the main channel. The cooperative jamming group uses the main channel null space to transmit artificial noise which does not affect the quality of the main channel, but reduces the eavesdropping channel quality. Simulation results show that the proposed anti-eavesdropping scheme can maximize the quality dif-ference between the main channel and the eavesdropping channels, which thereby may significantly improve the se-curity capacity of satellite downlink systems.