Downlink Non-Orthogonal Multiple Access Systems with an Untrusted Relay

Ahmed Arafa, Wonjae Shin, Mojtaba Vaezi, H. Vincent Poor

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

2 Scopus citations

Abstract

A downlink single-input single-output (SISO) non-orthogonal multiple access (NOMA) system in which a base station (BS) is communicating with two users is considered. An untrusted half-duplex relay node is available to assist with the BS's transmission. The BS uses superposition coding to transmit its messages, and the relay employs either a compress-and-forward or an amplify-and-forward scheme to communicate with the users. Two modes of operation are considered: passive user mode, and active user mode. In the passive user mode, the users receive data from both a direct link from the BS and the relay's forwarding link, and use that to decode their messages. In the active user mode, the users send a cooperative jamming signal simultaneously with the BS's transmission to confuse the relay. The focus is on half-duplex nodes, and hence the users cannot receive data from the BS's direct link in the active user mode while transmitting the cooperative jamming signal; they receive it only through the relay's forwarding link. For each mode, and under each relaying scheme, achievable secrecy rate regions are developed. Results show that the best relaying scheme and user mode depend on relative distances among the nodes, and on which part of the secrecy region the system is operating at.

Original languageEnglish (US)
Title of host publicationConference Record of the 52nd Asilomar Conference on Signals, Systems and Computers, ACSSC 2018
EditorsMichael B. Matthews
PublisherIEEE Computer Society
Pages1689-1693
Number of pages5
ISBN (Electronic)9781538692189
DOIs
StatePublished - Feb 19 2019
Event52nd Asilomar Conference on Signals, Systems and Computers, ACSSC 2018 - Pacific Grove, United States
Duration: Oct 28 2018Oct 31 2018

Publication series

NameConference Record - Asilomar Conference on Signals, Systems and Computers
Volume2018-October
ISSN (Print)1058-6393

Conference

Conference52nd Asilomar Conference on Signals, Systems and Computers, ACSSC 2018
CountryUnited States
CityPacific Grove
Period10/28/1810/31/18

All Science Journal Classification (ASJC) codes

  • Signal Processing
  • Computer Networks and Communications

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  • Cite this

    Arafa, A., Shin, W., Vaezi, M., & Poor, H. V. (2019). Downlink Non-Orthogonal Multiple Access Systems with an Untrusted Relay. In M. B. Matthews (Ed.), Conference Record of the 52nd Asilomar Conference on Signals, Systems and Computers, ACSSC 2018 (pp. 1689-1693). [8645185] (Conference Record - Asilomar Conference on Signals, Systems and Computers; Vol. 2018-October). IEEE Computer Society. https://doi.org/10.1109/ACSSC.2018.8645185