An Investigation of Using Loop-back Mechanism for Channel Reciprocity Enhancement in Secret Key Generation

Linning Peng, Guyue Li, Junqing Zhang, Roger Woods, Ming Liu, Aiqun Hu

Research output: Contribution to journalArticlepeer-review

44 Citations (Scopus)
537 Downloads (Pure)


Physical layer security key generation exploits unpredictable features from wireless channels to achieve high security, which requires high reciprocity in order to set up symmetric keys between two users. This paper investigates enhancing the channel reciprocity using a loop-back scheme with multiple frequency bands in time-division duplex (TDD) communication systems, in order to mitigate the effect of hardware fingerprint interference and synchronization offset. The scheme is evaluated to be robust to passive eavesdropping and active Man-in-the-Middle attack through both theoretical analyses and practical measurements. A secret key generation protocol is subsequently designed. The performance of the proposed secret key generation method is then evaluated through both numerical simulation and experiments. Results demonstrate that the proposed scheme can effectively mitigate non-reciprocity and outperforms the classical TDD scheme in both key disagreement rate and key generation rate.
Original languageEnglish
Article number8370120
Pages (from-to)507-519
Number of pages13
JournalIEEE Transactions on Mobile Computing
Issue number3
Publication statusPublished - 01 Mar 2019


  • Channel reciprocity
  • OFDM
  • USRP
  • channel state information
  • hardware fingerprint
  • loop-back transmission
  • physical layer security
  • secret key generation

ASJC Scopus subject areas

  • Software
  • Computer Networks and Communications
  • Electrical and Electronic Engineering


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