This letter focuses on the secure downlink multi-user generalized spatial modulation (MU-GSM) system based on the artificial noise (AN). Block diagonalization (BD) is firstly used to eliminate inter-user interference. In addition, the AN which has no impact on legitimate users is adopted to prevent eavesdropping for the first time in MU-GSM communication. Particularly, the proposed MU-GSM system can achieve satisfying security performance even without AN, which is different from the single-user scenario. Finally, the simulation results show that with AN protection and BD, the physical layer security can be significantly enhanced when compared with the random noise scheme and the multi-user precoding-aided spatial modulation.

中文翻译：

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用于多用户传输的人工噪声辅助安全广义空间调制

这封信重点介绍了基于人工噪声（AN）的安全下行多用户广义空间调制（MU-GSM）系统。块对角化（BD）首先用于消除用户间干扰。另外，在MU-GSM通信中首次采用了对合法用户没有影响的AN来防止窃听。特别是，所提出的 MU-GSM 系统即使没有 AN 也能达到令人满意的安全性能，这与单用户场景不同。最后，仿真结果表明，与随机噪声方案和多用户预编码辅助空间调制相比，通过AN保护和BD，可以显着增强物理层安全性。