Effective Secrecy Rate for a Downlink NOMA Network

Wenjuan Yu (1) , Arsenia Chorti (2) , Leila Musavian (3) , H Vincent Poor (4) , Qiang Ni (5)

1 State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences
2 ETIS - UMR 8051 - Equipes Traitement de l'Information et Systèmes
3 School of Computer Science and Electronic Engineering, University of Essex, Colchester, CO4 3SQ, UK
4 EE - Department of Electrical Engineering [Princeton]
5 SCC - School of Computing and Communications [Lancaster]

In this paper, a novel approach is introduced to study the achievable delay-guaranteed secrecy rate, by introducing the concept of the effective secrecy rate (ESR). This study focuses on the downlink of a non-orthogonal multiple access (NOMA) network with one base station, multiple single-antenna NOMA users and an eavesdropper. Two possible eavesdropping scenarios are considered: 1) an internal, unknown, eavesdropper in a purely antagonistic network; and 2) an external eavesdropper in a network with trustworthy peers. For a purely antagonistic network with an internal eavesdropper, the only receiver with a guaranteed positive ESR is the one with the highest channel gain. A closed-form expression is obtained for the ESR at high signal-to-noise ratio (SNR) values, showing that the strongest user's ESR in the high SNR regime approaches a constant value irrespective of the power coefficients. Furthermore, it is shown the strongest user can achieve higher ESR if it has a distinctive advantage in terms of channel gain with respect to the second strongest user. For a trustworthy NOMA network with an external eavesdropper, a lower bound and an upper bound on the ESR are proposed and investigated for an arbitrary legitimate user. For the lower bound, a closed-form expression is derived in the high SNR regime. For the upper bound, the analysis shows that if the external eavesdropper cannot attain any channel state information (CSI), the legitimate NOMA user at high SNRs can always achieve positive ESR, and the value of it depends on the power coefficients. Simulation results numerically validate the accuracy of the derived closed-form expressions and verify the analytical results given in the theorems and lemmas.

Mots clés: delay- outage probability; NOMA; Effective capacity; secrecy rate

Domaines: Traitement du signal et de l'image [eess.SP]; Cryptographie et sécurité [cs.CR]

Wenjuan Yu, Arsenia Chorti, Leila Musavian, H Vincent Poor, Qiang Ni. Effective Secrecy Rate for a Downlink NOMA Network. IEEE Transactions on Wireless Communications, 2019, ⟨10.1109/TWC.2019.2938515⟩. ⟨hal-02518659⟩