Towards a Win-Win Spectrum Sharing Channel: A Secrecy Perspective

摘要

Spectrum sharing and device-to-device (D2D) transmission are among the key features of modern communication networks. In this work, we are particularly interested in these two techniques from a sharing for secrecy perspective. The considered communication model consists of a multi-user cellular system and an underlying secondary system comprising K D2D pairs. All cellular and D2D transmissions are subject to an eavesdropping attack. Given a predefined secrecy condition, imposed by the primary system to guarantee a desired secrecy throughput, KS D2D pairs are allowed to share the spectrum and send their secret data while the remaining K-KS device transmitters operate as cooperative jammers. First, we characterize the achievable secrecy rates for both systems under a joint secrecy constraint on all transmitted cellular and D2D messages. Then, we propose a device selection scheme to determine the optimal number of devices, KS, that maximizes the secrecy throughput of the secondary system while satisfying the primary's secrecy condition. The obtained results show that both parties can win under the proposed transmission scheme; the cellular system can significantly improve its secrecy throughput, and the D2D pairs get to share the spectrum and achieve secure transmissions.