Secure Transmission on the Two-hop Relay Channel with Scaled Compute-and-Forward

Zhijie Ren, Jasper Goseling, Jos H. Weber, Michael Gastpar

Research output: Contribution to journalArticleScientificpeer-review

7 Citations (Scopus)


In this paper, we consider communication on a two-hop channel, in which a source wants to send information reliably and securely to the destination via a relay. We consider both the untrusted relay case and the external eavesdropper case. In the untrusted relay case, the relay behaves as an eavesdropper and there is a cooperative node which sends a jamming signal to confuse the relay when it is receiving from the source. In the external eavesdropper case, the relay is trusted and there is an external node eavesdropping the communication. We propose two secure transmission schemes using the scaled compute-and-forward technique. One of the schemes is based on a random binning code and the other one is based on a lattice chain code. It is proved that in the high Signal-to-Noise-Ratio (SNR) scenario and/or the limited relay power scenario, if the destination is used as the jammer, both schemes outperform all existing schemes and achieve the upper bound. In particular, if the SNR is large and
the source, the relay, and the cooperative jammer have identical power and channels, both schemes achieve the upper bound for secrecy rate, which is merely 1/2 bit per channel use lower than the channel capacity without secrecy constraints. We also prove that one of our schemes achieves a positive secrecy rate in the external eavesdropper case in which the relay is trusted and there
exists an external eavesdropper.
Original languageEnglish
Pages (from-to)7753-7769
Number of pages17
JournalIEEE Transactions on Information Theory
Issue number12
Publication statusPublished - 2017


  • Compute-and-forward
  • lattice codes
  • two-hop channel
  • untrusted relay
  • information theoretic security

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