## 3 Communication and Channel Modeling
### Efficiency with Multiple-Access Technologies and Cognitive Radio Communication
#### 3.3.2 Rate-Splitting Multiple Access  
RSMA has emerged as a generalized multiple-access technology that effectively manages interference in multi-user communication systems [78]. RSMA is particularly beneficial for UAV-enabled, RIS-assisted communication in multi-user IoV networks, enabling efficient operation within the same spectrum [79]. The optimal RSMA power allocation coefficients for UAV-RIS-IoV links are determined by minimizing the sum of the average outage probability (AOP) across all targeted vehicles.  
\begin{table}
\begin{tabular}{l l l l l l l l l l} \hline \hline \multirow{2}{*}{**Refs.**} & \multirow{2}{*}{**Navigation and Content**} & \multicolumn{2}{c}{**Application**} & \multicolumn{2}{c}{**Communication**} & \multicolumn{2}{c}{**Organization Problem**} \\ \cline{3-10}  & & & **Service** & **EWS Type** & **Channel Model** & **MA** & **Technology** & **Off** & **Functionalization** & **Constation** & **Optimizer** \\ \hline
[9] & 20 Depth & Ground UE & UAV-RIS & Rician channel & – & Max Area & Convex & – & Convex solver CVX \\  & 20-RIS-Pikh & Ground UE & UAV-RIS & Rician channel & – & Ach. rate & Programming & – & Convex solver CVX \\ \hline
[4] & 20 Depth & multi-cell & & & & & & & & \\  & 28-Pikh & multi-cell-multiple-user & & RSMA/AV & Rician channel & – & Min Area & SCA & BS power & Convex solver CVX \\ \hline
[8] & 20 Depth & Throughput & RSMA/AV & Deterministic LoS & – & More throughput & – & & & & \\  & 28-Pikh & & maximization & RSMA/AV & Deterministic LoS & – & throughput & optimization & Speed, Power & programming \\ \hline
[9] & 30-Pikhaped & LoS & UAV-RIS & Probabilistic & – & Max & Block-centric & Velocity & & \\  & 28-Pikhaped & LoS & UAV-RIS & LoS & – & Ach. rate & Adomom-SCA & Acceleration & & \\ \hline
[1] & 20 Depth-Pikhaped & MTC & UAV-RIS & Probabilistic & – & EE & SCA & QoS & Convex solver CVX \\  & 28-Pikh & & & & & & & & & \\  & 28-Pikh & & & & & & & & & \\  & 28-Pikh & & & & & & & & & \\ \hline
[10] & 20 Depth & Ground node & RSMA/AV & Probabilistic LoS & – & Max & MINP & Linear & & \\  & 20-Pikh & & & & & & & & & \\  & 20-Pikh & Security & RSMA/AV & Free space loss & – & EE & MDP & Power & & & \\  & 28-Pikh & & & & & & & & & \\  & 20-Pikh & Physical layer security & RSMA/AV & Probabilistic & – & Espodia & – & & & \\  & 28-Pikh & & security & RSMA/AV & LoS & – & Security & Non-convex & QoS, SINR & & Convex solver CVX, PSO, SA \\ \hline
[5] & 30-Pikhoured & Multiple ULPs & RSMA/AV & LoS & UAV-RIS & NORMAL & Max & SCA & – & CVX above \\  & 28-Pikh & & & & & & & & & \\  & 28-Pikh & Ground UE & RSMA/AV & Probabilistic & LoS & NORMAL & Ach. rate & SEOP & – & PSO \\ \hline
[7] & 30-Pikhoured & GUs & TX-UAV & Probabilistic & & Block-centric & & & & & \\  & 28-Pikh & & & & & & & & & \\ \hline
[8] & 30-Pikhoured & GUs & TX-UAV & Euclidean-LoS & RSMA & WSDR & SCA & Min Rate and & & \\  & 28-Pikh & & & & & & & & & \\  & 28-Pikh & & & & & & & & & \\ \hline
[8] & 30-Pikhoured & Block-CIM & UAV-RIS & Rician fading & – & EE (RF) + SR & MINP & Min-SR, Power & RCD. Adom-iCA \\ \hline
[8] & 30-Pikhoured & Connectivity & Antil-network & & & small-scale & – & Min Max WCSR & MDP & Min DR, & \\  & 28-Pikh & end-spin & antil-spin & – & – & Min Area & WCSR & MDP & & & \\  & 28-Pikh & end-spin & – & & & & & & & \\ \hline
[8] & 30-Pikhoured & Area & BS-UAV & Euclidean-LoS & NORMAL & Min-SE & SCA & Min DR, & & DBL-DGN \\  & 28-Pikh & end-spin & & STAR-RIS & & & & & & \\ \hline
[10] & 30-Pikhoured & Matching & & & & & & & & \\  & 28-Pikh, & end-spin & & & & & & & & \\  & 28-Pikh & & & & & & & & \\ \hline
[11] & 30-Pikhoured & Matching & & & & & & & & \\  & 28-Pikh & end-spin & & &