Secure backscatter communications in multi-cell NOMA Networks: Enabling link security for massive IoT networks

Wali Ullah Khan*, Ju Liu, Furqan Jameel, Muhammad Toaha Raza Khan, Syed Hassan Ahmed, Riku Jäntti

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review


Non-orthogonal multiple access (NOMA) and backscatter communications are considered to be promising technologies due to their applications in large-scale Internet-of-things (IoT) networks for ensuring low-powered and spectral-efficient communication. However, massive connectivity of IoT devices may result in compromising the link security, resulting in information leakage to eavesdroppers. To solve this issue, we consider a multi-cell backscatter network where a base station (BS) in each cell communicates to cellular users using the power-domain NOMA technique. A backscatter node in each cell also receives the superimposed signal from BS, utilizes this signal to modulate data and, then, retransmit it to nearby cellular user in the presence of multiple eavesdroppers. The eavesdroppers in the vicinity may try to overhear the transmission of the backscatter node due to the broadcast nature of the wireless network. Therefore, we investigate an optimization problem to maximize the secrecy rate of the NOMA-enabled multi-cell backscatter network. In particular, we optimize the reflection coefficient of the backscatter node in the presence of multiple eavesdroppers in each cell. The optimization problem is formulated as a convex problem that is subjected to the maximum reflection coefficient of the backscatter node. To obtain an optimal solution, we exploit Karush-Kuhn-Tucker conditions where the Lagrangian multipliers are updated by the sub-gradient method. We also present the secrecy maximization problem under traditional time division multiple access (TDMA) for the sake of comparison. Finally, the results are obtained using the Monte Carlo simulation which demonstrates that the proposed NOMA scheme significantly outperforms the traditional TDMA scheme.

Original languageEnglish
Title of host publicationIEEE INFOCOM 2020 - IEEE Conference on Computer Communications Workshops, INFOCOM WKSHPS 2020
Number of pages6
ISBN (Electronic)9781728186955
Publication statusPublished - Jul 2020
MoE publication typeA4 Article in a conference publication
EventIEEE Conference on Computer Communications - Online, Toronto, Canada
Duration: 6 Jul 20209 Jul 2020
Conference number: 38


ConferenceIEEE Conference on Computer Communications
Abbreviated titleINFOCOM


  • Backscatter communication
  • Dual theory
  • Internet-of-things
  • Non-orthogonal multiple access
  • Secrecy rate

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