Evaluating secrecy performance of cooperative NOMA networks under existence of relay link and direct link

Abstract

Summary The secrecy performance of a nonorthogonal multiple access (NOMA) system is examined in this study by employment of a dual‐hop decode‐and‐forward (DF) relay under existence of eavesdropper. Due to the fact that the relay is trusted or untrusted device and thus eavesdropper may wiretap information from the base station or the relay. In this regard, three scenarios related to trusted and untrusted relays are proposed, with different assumptions on the information overhearing ability of the eavesdropper; ie, the first scenario is that an eavesdropper overhears signal from the relay while the BS is overheard by eavesdropper in the second scenarios. More specifically, we derive closed‐form expressions for the secure probability metrics when the direct and relay links experience independent Rayleigh fading. There metrics include strictly positive secrecy capacity (SPSC) and the secure outage probability (SOP). Furthermore, secure performance of traditional orthogonal multiple access (OMA) is also provided as further comparison with NOMA counterpart. We analyze the influence of main coefficients such as the target rates and the transmit SNR factors on the secrecy performance. Our results specify that for reasonable selection of such parameters, secrecy performance can be enhanced remarkably. Numerical results are delivered to corroborate the derived results.

Study on transmission over Nakagami-m fading channel for multiple access scheme without orthogonal signal

“…In this case, the PDF and CDF of the user channel gain |ℎ | 2 can be expressed. The PDF and CDF of channel ℎ [24] are (9) And (10) respectively, where |ℎ | stands for channel transmitting from the BS to an arbitrary user. It is noted that those channels are unsorted channel gain.…”

“…To satisfy requirements of fifth-generation (5G) networks, many researchers have believed that NOMA can be implemented effectively to meet both user-experienced and network level data rate [7]. In recent research, possible applications together with point-to-point NOMA has been studied comprehensively in [8][9][10][11]. In [8], downlink NOMA with randomly deployed users is examined in terms of the outage performance and ergodic rate by invoking tool of stochastic geometry.…”

“…In [8], downlink NOMA with randomly deployed users is examined in terms of the outage performance and ergodic rate by invoking tool of stochastic geometry. To against outside eavesdroppers as performing the secrecy analysis in NOMA [9]. In the scenario of single-antenna and multiple-antenna transmission, the secrecy outage probability of NOMA is exploited in situation of larger scale networks [9].…”

“…To against outside eavesdroppers as performing the secrecy analysis in NOMA [9]. In the scenario of single-antenna and multiple-antenna transmission, the secrecy outage probability of NOMA is exploited in situation of larger scale networks [9]. A unique framework for hybrid satellite/unmanned aerial vehicle terrestrial NOMA networks was studied, in which ground users comunicate with satellite aims be exploiting NOMA protocol and the assistance of a decodeforward (DF) UAV relay [10].…”

Optimal power allocation‐based novel control jamming scheme for nonorthogonal multiple access enabled decode‐and‐forward relay network

“…In this study, secrecy performance is examined for both trusted and untrusted relay networks by varying target rates and power allocation factors. 22 In addition, SOP and secrecy capacity of a DF relay-assisted NOMA network is also examined in multi-relay scenario. 23,24 Further, to enhance the secrecy sum rate, in Garcia et al 25 the authors proposed particle swarm optimization (PSO)-based power allocation scheme for a NOMA network with DF relaying.…”