MIMO broadcast channel with an unknown eavesdropper: Secrecy degrees of freedom

Xiang He, Ashish Khisti, Aylin Yener

    Research output: Contribution to journalArticlepeer-review

    14 Scopus citations


    We study a multi-antenna broadcast channel with two legitimate receivers and an external eavesdropper. We assume that the channel matrix of the eavesdropper is unknown to the legitimate terminals but satisfies a maximum rank constraint. As our main result we characterize the associated secrecy degrees of freedom for the broadcast channel with common and private messages. We show that a direct extension of the single-user wiretap codebook does not achieve the secrecy degrees of freedom. Our proposed optimal scheme involves decomposing the signal space into a common subspace, which can be observed by both receivers, and private subspaces which can be observed by only one of the receivers, and carefully transmitting a subset of messages in each subspace. We also consider the case when each user's private message must additionally remain confidential from the other legitimate receiver and characterize the s.d.o.f. region in this case.

    Original languageEnglish (US)
    Article number6679362
    Pages (from-to)246-255
    Number of pages10
    JournalIEEE Transactions on Communications
    Issue number1
    StatePublished - Jan 2014

    All Science Journal Classification (ASJC) codes

    • Electrical and Electronic Engineering


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