Outage Performance for Cooperative NOMA Transmission with an AF Relay

Abstract

Abstract-This letter studies the outage performance of cooperative non-orthogonal multiple access (NOMA) network with the help of an amplify-and-forward relay. An accurate closed-form approximation for the exact outage probability is derived. Based on this, the asymptotic outage probability is investigated, which shows that cooperative NOMA achieves the same diversity order and the superior coding gain compared to cooperative orthogonal multiple access. It is also revealed that when the transmit power of relay is smaller than that of the base station, the outage performance improves as the distance between the relay and indirect link user decreases.Index Terms-Outage probability, non-orthogonal multiple access, amplify-and-forward, relaying networks.

Physical Layer Security for Cooperative NOMA Systems

“…The results in [5] show that the proposed TSRS outperforms the conventional max-min relay selection criteria. More recently, the authors in [6] studied a cooperative NOMA scenario with the help of an AF relay and derived an approximate outage probability expression.…”

A Tutorial on Nonorthogonal Multiple Access for 5G and Beyond

“…In this context, in [82], a coordinated transmission protocol where a user communicates with BS directly while the other needs the help of a relay to receive the transmitted information from the BS has been employed in NOMA scheme in order to improve the spectral efficiency, and OP analysis is conducted for frequency-flat block fading channels by using DF relaying, as shown in Figure 8(a). In [83], the same scenario in [82] is considered, and OP and asymptotic expressions are obtained in approximated closed forms for AF relaying networks. Differing from [82] and [83], in [84], the authors proposed a cooperative relaying system, where two symbols transmitted from the BS to the user by the help of a relay were combined at the BS by applying NOMA concept.…”

“…In [83], the same scenario in [82] is considered, and OP and asymptotic expressions are obtained in approximated closed forms for AF relaying networks. Differing from [82] and [83], in [84], the authors proposed a cooperative relaying system, where two symbols transmitted from the BS to the user by the help of a relay were combined at the BS by applying NOMA concept. The exact and asymptotic expressions related to achievable average rate are derived in i.i.d.…”

Cooperative NOMA with full‐duplex amplify‐and‐forward relaying

“…In addition, they showed that their system attains higher ergodic sum rate in the low to moderate signal‐to‐noise ratio (SNR) range. Liang et al investigated the outage performance of a NOMA system with an amplify‐and‐forward half‐duplex (AF‐HD) relay, and they indicated that their system outperforms a cooperative OMA system.…”