Coding schemes for confidential communications

Xiaojun Tang, Ruoheng Liu, Predrag Spasojević, H. Vincent Poor

Research output: Chapter in Book/Report/Conference proceedingConference contribution


In this paper, the hybrid automatic retransmission request (HARQ) coding scheme is revisited for a block-fading wire-tap channel, in which two legitimate users communicate over a block-fading channel in the presence of a passive eavesdropper who intercepts the transmissions through an independent block-fading channel. In this model, the transmitter obtains a 1-bit ACK/NACK feedback from the legitimate receiver via an error-free public channel. Both reliability and confidentiality of secure HARQ protocols are studied by the joint consideration of channel coding, secrecy coding, and retransmission protocols. In particular, the error and secrecy performance of repetition time diversity (RTD) and incremental redundancy (INR) schemes are investigated based on good Wyner code sequences, which ensure that the confidential message is decoded successfully by the legitimate receiver and is kept in total ignorance by the eavesdropper for a given set of channel realizations. This paper first illustrates that there exists a good rate-compatible Wyner code family which ensures a secure INR protocol. Next, two types of outage probabilities, connection outage and secrecy outage probabilities are defined in order to characterize the tradeoff between the reliability of the legitimate communication link and the confidentiality with respect to the eavesdropper's link. For a given connection/secrecy outage probability pair, an achievable throughput of secure HARQ protocols is derived for blockfading channels. Finally, both asymptotic analysis and numerical computations demonstrate the benefits of HARQ protocols to throughput and secrecy.

Original languageEnglish (US)
Title of host publication2008 Information Theory and Applications Workshop - Conference Proceedings, ITA
Number of pages10
StatePublished - 2008
Externally publishedYes
Event2008 Information Theory and Applications Workshop - ITA - San Diego, CA, United States
Duration: Jan 27 2008Feb 1 2008

Publication series

Name2008 Information Theory and Applications Workshop - Conference Proceedings, ITA


Other2008 Information Theory and Applications Workshop - ITA
Country/TerritoryUnited States
CitySan Diego, CA

All Science Journal Classification (ASJC) codes

  • Computer Science Applications
  • Information Systems


Dive into the research topics of 'Coding schemes for confidential communications'. Together they form a unique fingerprint.

Cite this