CREAM: Unauthorized Secondary User Detection in Fading Environments

Dynamic Spectrum Access (DSA) has emerged as a major technology in the future wireless system to alleviate the worldwide spectrum scarcity issue. Authorized secondary users can take advantages of underutilized spectrum for communication. However, due to the open nature of the wireless medium, the DSA system suffers spectrum misuse by unauthorized secondary users, and thus fewer users would participate in DSA. Although many existing works have implemented misuse detection schemes into DSA, practical concerns, such as channel fading issues, are not well addressed. Therefore, how to ensure the reliable communication among authorized secondary users in a practical channel model becomes a challenging issue. In this paper, we propose CREAM, a physical-layer based misuse detection scheme specifically in the fading environment, which conceals the unforgeable spectrum permit into the message by superposition modulation for verification. Given the pre-shared secret information, the third-party verifier can perform efficient detection on unauthorized spectrum access. Detailed analysis and simulation results demonstrate the security, accuracy, efficiency, and low intrusion to message transmission in fading environments.

动态频谱接入（DSA）已成为未来无线系统中缓解全球频谱稀缺问题的一项关键技术。授权的次要用户可利用未充分利用的频谱进行通信。然而，由于无线介质的开放性，DSA系统会遭受未授权次要用户的频谱滥用问题，从而导致参与DSA的用户减少。尽管许多现有研究已在DSA中实施了滥用检测方案，但一些实际问题，比如信道衰落问题，并未得到很好的解决。因此，如何在实际信道模型中确保授权次要用户之间的可靠通信成为一个具有挑战性的问题。在本文中，我们提出了CREAM，一种专门针对衰落环境的基于物理层的滥用检测方案，该方案通过叠加调制将不可伪造的频谱许可隐藏在消息中以进行验证。给定预共享的秘密信息，第三方验证者能够对未授权的频谱接入进行高效检测。详细的分析和仿真结果证明了其在衰落环境中的安全性、准确性、高效性以及对消息传输的低干扰性。