# Resource Management in Converged Optical and Millimeter Wave Radio Networks: A Review
## 3 Research Method and Overview of Selected Articles
### Research Method  
In order to conduct this survey, we reviewed works published in the literature with a focus on those that cover most of the identified optimization requirements for converged optical fronthaul and mmWave wireless access networks. Before presenting these works, inthe following we explain our research method based on the research steps given in [40]. The selection procedure is also illustrated in Figure 2.  
The first step was the selection of the papers. We completed this step by conducting database searches in the ACM, Elsevier (Science Direct), IEEE, IET, MDPI, Optical Society/Optica (OSA), Springer, Taylor & Francis, and Wiley online library databases with keywords _\"resource allocation AND converged mmWave fiber wireless (FiWi)\", \"resource management AND converged mmWave fiber wireless (FiWi)\"_, and _\"resource allocation AND converged fiber wireless (FiWi)\"_. The searches in all databases were completed in May 2021. The resulting collection was screened, to exclude non-scientific texts, book chapters, out of context papers, and survey papers. The full list of papers can be found in [41].  
Among the remaining 189 papers found in our database search, our selection criteria was created to present the works that are most relevant to the target network architecture, providing novel implementation solutions to the requirements of the optimization objective. The criteria selected for our eligibility step can be summarized as follows:  
Figure 2: Paper selection phases of the review [40].  
* The study provided a sound research approach and published after a scholarly review process;
* The study had a resource management optimization objective for mmWave networks;
* The study explained the system model and proposed a well-defined optimization algorithm;
* The effects of the algorithm on a performance metric was reported and the different aspects of the performance metric were analyzed with different evaluation criteria.  
This review is limited to the focus scope on converged optical and mmWave radio network solutions and to the databases taken into consideration. The prioritization of the works that address a well-defined optimization algorithm led to the omission of relevant papers. We did not include works that do not clearly define a resource management objective, e.g., a study that focuses on the the hardware implementation aspects of optical and mmWave radio networks with no resource management perspective. We manually excluded all studies that do not match these criteria with a simple scoring system, in which a point is deducted from an eligible paper for each missing criterion. After this screening process, we identified 37 papers that focused on at least one of the resource management objectives of throughput maximization (Section 4), delay minimization (Section 5), energy-efficiency (Section 6), and virtualized resource allocation (Section 7). The papers that have joint objectives are classified under their main optimization focus of that paper. Our target in this review is to understand the recent optimization techniques used in resource allocation for converged optical fronthaul and radio mmWave access network implementations, therefore we focused our search to the works completed in the last five years (between 2016 and 2021, both included), and approximately 95% of the selected papers fit in this category.