# Resource Allocation Schemes for 5G Network: A Systematic Review
## 4 Design of Research
### Article Selection Process  
The perspective of a research article was the predominant way through which several quantitative kinds of research were selected. Quality assessment principles were applied to certain articles to determine their exclusion and inclusion. The tactic used to select the articles started with formulating the research questions, as mentioned above. Outlining the string of searches supported the search and selection procedure. Only English language articles were studied in this review. The PRISMA flow diagram [68; 69] was followed and is shown in Figure 5. After obtaining the initial research articles based on the strings and keywords, we reviewed how resource allocation schemes in 5G communication were addressed in each article. The search procedure finished by classifying the resource allocation scheme to ensure the comprehensiveness of this study. Several papers were eliminated due to a mismatch between their titles and the strength of the measures that were used. Additionally, abstracts on their own were not considered for inclusion in this study.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Publisher** & **URL** \\ \hline MDPI & [[https://www.mdpi.com](https://www.mdpi.com)]([https://www.mdpi.com](https://www.mdpi.com)) (accessed on: 1 July 2021) \\ \hline Science Direct & [[https://www.sciencedirect.com](https://www.sciencedirect.com)]([https://www.sciencedirect.com](https://www.sciencedirect.com)) (accessed on 15 June 2021) \\ \hline Wiley Online Library & [[https://onlinelibrary.wiley.com](https://onlinelibrary.wiley.com)]([https://onlinelibrary.wiley.com](https://onlinelibrary.wiley.com)) (accessed on 20 June 2021) \\ \hline Springer & [[https://link.springer.com](https://link.springer.com)]([https://link.springer.com](https://link.springer.com)) (accessed on 25 May 2021) \\ \hline Sage & [[https://journals.sagepub.com](https://journals.sagepub.com)]([https://journals.sagepub.com](https://journals.sagepub.com)) (accessed on 12 May 2021) \\ \hline Google Scholar & [[https://scholar.google.com](https://scholar.google.com)]([https://scholar.google.com](https://scholar.google.com)) (accessed on 25 July 2021) \\ \hline ACM & [[https://www.acm.org](https://www.acm.org)]([https://www.acm.org](https://www.acm.org)) (accessed on 20 May 2021) \\ \hline IEEE & [[https://ieeexplore.ieee.org](https://ieeexplore.ieee.org)]([https://ieeexplore.ieee.org](https://ieeexplore.ieee.org)) (accessed on 28 June 2021) \\ \hline \hline \end{tabular}
\end{table}
Table 2: Data Sources.  
Figure 5: Article selection procedure [68; 69].  
As presented in Figure 5, a total of 1139 research articles were collected using the search strings, as a result of the aforementioned inquiry. The articles were published from the year 2015 to 2020 in various quality journals and other publications, as presented in Table 2. To select compelling research articles, the criteria of inclusion and exclusion were applied, as shown in Table 3, to reduce their number to 627. Based on the abstracts and titles, the selection was reduced to 122 articles related to the selected domain. From this point onward, these 122 articles were examined, and they were categorized bases on their resource allocation techniques as conventional or artificially intelligent in 5G communication: 71 articles were ultimately selected.  
Depending on the selection criteria, the most relevant articles based on abstracts, title, and comprehensive research were selected, ensuring that the results would be relevant to the research work as desired.