# An Optimal Resource Allocation Scheme with Carrier Aggregation in 5G Network under Unlicensed Band
## 2 Related Literature  
In [8], the total throughput of both downlink and uplink in 5G New Radio (5G NR) in an unlicensed channel spectrum is maximized by jointly optimizing the time and power allocation during the maximum channel occupation time duration while ensuring a fair coexistence with Wi-Fi. Meanwhile, previous research [22] derives explicit expressions of the maximum total network effective throughput and the corresponding optimal initial backoff window sizes of Wi-Fi and NR-unlicensed nodes. However, throughput is the only network performance metric considered in these papers and it leads to the preference for offloading the cellular traffic and best-effort transmissions by the Wi-Fi system. In [23], the authors investigate a 5G network with virtual network function-based reusable functional blocks and the total cost of the network is minimized by two algorithms derived by the authors. In [24], recent advances in technical standards and critical enabling techniques were reviewed. Moreover, the authors proposed and analyzed a novel hardware reuse and multiplexing solution to facilitate cost-effective and energy-efficient UE design. The authors in [13] provided an overview of CA, which is visualized as critical for 5G and upcoming networks. In [25], the transmission space was divided into two subspaces to allow for the coexistence of cellular users, Internet of Things devices, and Wi-Fi users. Meanwhile,  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Definition** \\ \hline \(p_{iu}^{t}\) & received power at UE \(u\) from AP \(i\) \\ \hline \(p_{iu}^{t}\) & transmit power from node \(i\) to node \(u\) \\ \hline \(g_{iu}\) & channel gain \\ \hline \(d_{iu}\) & distance between node \(i\) and node \(u\) \\ \hline \(V_{i}\) & Voronoi cell \(i\) \\ \hline \(\mathbf{U}_{i}\) & set of UEs associated with the AP \(i\) \\ \hline \(N^{I}\) & the number of APs from set \(I\) \\ \hline \(N^{I}\) & the number of APs from set \(J\) \\ \hline \(d_{iu}\) & distance from \(u\) to \(i\) \\ \hline \(d_{iu}\) & distance from \(u\) to \(j\) \\ \hline \(\lambda_{I}\) & density of APs from \(I\) \\ \hline \(\lambda_{J}\) & density of APs from \(J\) \\ \hline CDF & cumulative distribution function \\ \hline SINR & signal-to-interference-plus-noise \\ \hline \(\beta\) & threshold for the received SINR \\ \hline \(\mathbf{Ic}_{i}\) & co-channel interference power set \\ \hline \(\sigma^{2}\) & white Gaussian noise \\ \hline \(\mathbf{\Phi}\) & interference set \\ \hline \(C_{w}\) & mean ergodic achievable rate \\ \hline \(b_{w}\) & virtual carrier bandwidth for Wi-Fi AP to UE \\ \hline \(p_{w}^{t}\) & transmit power for Wi-Fi AP to UE \\ \hline \hline \end{tabular}
\end{table}
Table 1: _Cont._the cellular system throughput is maximized via the joint power and subchannel allocation under the interference constraint. Ref. [26] made a single-fed dual-band circular polarized dielectric resonator antenna for dual-function communication, which is a decent candidate for a global positioning system and wireless local area network. However, as the most distinguishing feature, variable QoS requirements for multiple types of services are not considered in these existing works, which requires a more efficient coexistence mechanism based on the network performance, and this need motivates this paper.