Carrier Frequency Offset Based Shared Randomness for Secure Transmission in M-PSK NOMA


Goztepe C., Kurt G. K., Ozbek B.

2023 IEEE International Black Sea Conference on Communications and Networking, BlackSeaCom 2023, İstanbul, Turkey, 4 - 07 July 2023, pp.342-347 identifier

  • Publication Type: Conference Paper / Full Text
  • Doi Number: 10.1109/blackseacom58138.2023.10299798
  • City: İstanbul
  • Country: Turkey
  • Page Numbers: pp.342-347
  • Keywords: Carrier frequency offset, non-orthogonal multiple access (NOMA), perfect secrecy, physical layer security, software-defined radio
  • Istanbul Technical University Affiliated: Yes

Abstract

Power domain non-orthogonal multiple access (NOMA) enhances spectral efficiency by superposing multiple users in the same time-frequency resource block at the expense of exposing the users' data. However, current approaches to improve the secrecy levels of users are limited to rate reduction. This paper proposes a secure NOMA system based on the shared randomness extracted from the reciprocal carrier frequency offsets (CFOs) between the transmitter-receiver pairs for M-ary phase-shift keying. As multiple users will have physically separated oscillators, it will result in independent CFOs among users. This randomness is used to introduce a constellation rotation in the transmitted symbols. We show that under ideal CFO estimates, the proposed approach achieves perfect secrecy among all NOMA users without introducing any rate reduction. We also demonstrate the practical applicability of the proposed approach by using a software-defined radio-based test bed.