在中繼網路中, 可靠的實體層安全機制是傳輸成功與否的關鍵, 兩個典型的議題分別是自私的中繼行為以及竄改傳輸訊息, 在文獻中已經有很多方案被提出來解決這些問題。事實上, 有一種非典型但具破壞性的惡意行為可以使得合作式通訊的多樣性增益消失, 在本篇論文中, 我們使用”偽裝”(masquerade) 象徵這樣的惡意行為, 帶有這種惡意行為的中繼點會假裝自己是通道狀況最好的中繼點同時剝奪其他中繼點合作的可能性。我們發現這種惡意行為的偵測機制尚未被開發出來, 因此在本篇論文中, 我們提出了”likelihoodmasquerade detection”(LMD)方案以復原分散式中繼網路中的多樣性增益,LMD的運作方式是去計算選中的中繼點合作與惡意的機率大小, 如果某個中繼點惡意機率比較大的次數超過系統設定的閥值, 系統就會判定此中繼點有惡意行為。在模擬結果的章節中, 我們將以”通道容量”以及”中斷機率”來展示使用了LMD 後的系統表現, 另外也會對於在LMD 上做功率控制進行討論。

In the relay network, trustworthy physical layer security is the key to its successful applications. Two typical issues of physical layer security are selfishness and garbling. In the literature, many schemes have been proposed to address these issues. In fact, a certain non-typical but severely harmful misbehavior can also thoroughly remove the cooperative diversity gain from the relay network. Here, we coin ”masquerade” to clearly indicate this kind of misbehavior. A masquerade relay is the malicious one who can always pretend to be the best and consequently deprive the others of the opportunities to cooperate. To the best of our knowledge, the masquerade misbehavior detection has not yet been investigated. Thus, in this paper, we propose a likelihood masquerade detection (LMD) scheme to recover the cooperative diversity gain in the distributed relay networks. In LMD, the probability of the selected relay to be a cooperative one (Pc) and that to be a masquerade one (Pm) are first calculated. Afterwards, the masquerade relay can be sentenced when Pm > Pc occurs more frequently than a predefined threshold. The simulation results prove the effectiveness of the proposed LMD scheme in terms of capacity and outage probability. The impact of the power control mechanism on the masquerade detection is also discussed.

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