# Performance of Cooperative Relay NOMA with Large Antenna Transmitters
## 1 Introduction
### Motivation
\begin{table}
\begin{tabular}{p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt}} \hline \hline
**Ref** & \begin{tabular}{c} **Coding** \\ **Scheme** \\ \end{tabular} & \begin{tabular}{c} **Channel Model** \\ \end{tabular} & \begin{tabular}{c} **Transmission** \\ **Mode** \\ \end{tabular} & \
\begin{tabular}{c} **Performance Metrics** \\ \end{tabular} &
\begin{tabular}{c} **Outcome** \\ \end{tabular} \\ \hline
[47] & DF relay & \begin{tabular}{c} CBSM (Saleh- \\ Valenzuela), \\ multiple antenna \\ \end{tabular} & \begin{tabular}{c} Downlink \\ multiple antenna \\ \end{tabular} & \
\begin{tabular}{c} Achievable sum rate \\ \end{tabular} &
\begin{tabular}{c} The spectrum and energy efficiency of \\ beamspace MIMO are higher than those of \\ conventional beamspace systems. \\ \end{tabular} \\ \hline
[61] & AF relay & \begin{tabular}{c} CBSM (Rayleigh), \\ multiple antenna \\ \end{tabular} & \begin{tabular}{c} Downlink \\ multiple antenna \\ \end{tabular} & \
\begin{tabular}{c} Spectral efficiency \\ \end{tabular} &
\begin{tabular}{c} The number of BS antennas enhances system \\ spectral efficiency. \\ \end{tabular} \\ \hline
[77] & DF relay & \begin{tabular}{c} CBSM (Rayleigh), \\ single antenna \\ \end{tabular} & \begin{tabular}{c} Downlink \\ multiple antenna \\ \end{tabular} & \
\begin{tabular}{c} Diversity gain, outage \\ probability \\ \end{tabular} &
\begin{tabular}{c} A two-stage relay with DF achieves maximum \\ diversity gain while reducing outage probability. \\ \end{tabular} \\ \hline
[78] & AF relay & \begin{tabular}{c} CBSM (Rayleigh), \\ multiple antenna \\ \end{tabular} & \begin{tabular}{c} Downlink \\ multiple antenna \\ \end{tabular} & \
\begin{tabular}{c} Outage probability \\ throughput and \\ diversity gain \\ \end{tabular} &
\begin{tabular}{c} MIMO improves outage probabilities, but that \\ depends on the relay location. \\ \end{tabular} \\ \hline
[79] & AF buffer- & \begin{tabular}{c} CBSM (Rayleigh), \\ single antenna \\ \end{tabular} & \begin{tabular}{c} Downlink \\ single antenna \\ \end{tabular} & \
\begin{tabular}{c} Outage probability, \\ throughput and \\ diversity gain \\ \end{tabular} &
\begin{tabular}{c} Improve outage probability with increase buffer \\ size. Incorporating channel-to-packet matching \\ enhances system performance. Optimal selection \\ of buffer size provides a significant delay. \\ \end{tabular} \\ \hline
[80] & DF relay & \begin{tabular}{c} CBSM (Rician), \\ single antenna \\ \end{tabular} & \begin{tabular}{c} Downlink \\ multiple antenna \\ \end{tabular} & \
\begin{tabular}{c} Achievable rate \\ \end{tabular} &
\begin{tabular}{c} Gauss-Chebyshev interpolation is efficient to \\ approximate achievable rate. \\ \end{tabular} \\ \hline
[81] & DF relay & \begin{tabular}{c} CBSM (Rayleigh), \\ single antenna \\ \end{tabular} & \begin{tabular}{c} Downlink \\ multiple antenna \\ \end{tabular} & \
\begin{tabular}{c} Achievable sum rate \\ \end{tabular} &
\begin{tabular}{c} Configurable decoding achieves high sum rate \\ even under strong inter-user interference \\ and SNR. \\ \end{tabular} \\ \hline
[82] & DF relay & \begin{tabular}{c} CBSM (Rayleigh), \\ single antenna \\ \end{tabular} & \begin{tabular}{c} Multi-relay \\ Downlink \\ \end{tabular} & \
\begin{tabular}{c} Outage probability and \\ ergodic sum-rate \\ \end{tabular} &
\begin{tabular}{c} In comparison to typical NOMA and OMA \\ systems, the ergodic sum rate and outage \\ probability are enhanced. \\ \end{tabular} \\ \hline
[83] & DF relay & \begin{tabular}{c} CBSM (Rayleigh), \\ multiple antenna \\ \end{tabular} & \begin{tabular}{c} Downlink \\ diversity order \\ \end{tabular} & \
\begin{tabular}{c} Outage probability and \\ diversity order \\ \end{tabular} &
\begin{tabular}{c} A combination of antenna-and-relay selection \\ strategies can provide optimal outage \\ performance and diversity order that \\ outperforms conventional systems. \\ \end{tabular} \\ \hline
[84] & DF relay & \begin{tabular}{c} CBSM (Rayleigh), \\ multiple antenna \\ \end{tabular} & \begin{tabular}{c} Downlink \\ multiple antenna \\ \end{tabular} & \
\begin{tabular}{c} Secrecy outage probability \\ probability \\ \end{tabular} &
\begin{tabular}{c} There is better outage performance of the system \\ even in the presence of a jamming signal. \\ \end{tabular} \\ \hline
[85] & AF and \begin{tabular}{c} CBSM (Rayleigh), \\ multiple antenna \\ with energy \\ harvesting (EH) \\ capabilities \\ \end{tabular} & \begin{tabular}{c} Downlink \\ multiple antenna \\ with energy \\ harvesting (EH) \\ capabilities \\ \end{tabular} & \
\begin{tabular}{c} Average sum-rate and \\ secrecy rate \\ \end{tabular} &
\begin{tabular}{c} The position of the relay is crucial for maximum \\ performance. To maximize the secrecy rate, the \\ EH time duration must be carefully considered. \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table}