Towards 6G Technology: Insights into Resource Management for Cloud RAN Deployment

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper is devoted to a broad review of scientific achievements in the field of network/radio resource management in the 5G/6G radio domain working in the C/O-RAN architecture. The study did not present the proposed technologies in too many details, but focused on a broad set of research issues, which was supported by an extensive analysis of many scientific papers. The article was written in a quite readable way, maintaining moderate correctness of language and the order in which the theses and results of the analyzes were presented. The reviewer believes that the paper can be published after introducing a few additional clarifications, corrections and extensions:

1. The document should be formatted according to the IoT/MDPI template: https://www.mdpi.com/journal/IoT/instructions

2. The summary should primarily describe what has been done in the work, it should not be an introduction to the topic, so it should be rebuilt.

3. Line 31: if three service groups are mentioned, it is probably 5G (IMT-2020), not 6G (IMT-2030).

4. Figure 1: should be verified against IMT-2030 (ITU-R M.2160-0_2023.11)

5. The requirements defined under IMT-2030 should be at the forefront in the introduction.

6. Section 2: 4 points are presented, in relation to which the conclusion should include extensive explanations with description of the analysis results.

7. Subsection 4.1.2: There is no consideration of intelligent reflecting and energy recovery surfaces for local powering of reflecting structures. This is one of the main research topics conducted in the field of intelligent beamforming and routing of low-energy beams. This research topic should also be included in other subsections.

8. The summary should present which IMT-2030 requirements will be met in the C/O-RAN domain earlier than others and which of the analyzed technologies will ensure this.

9. The text of the study should be carefully reviewed to eliminate the so-called typos.

Comments on the Quality of English Language

Please eliminate the so-called typos.

Author Response

Thank you very much for taking the time to review this manuscript. 

I made the following:

1. Modified Figure 1 to meet requirements and services of 6G.
2. Remove the so-called typos.
3. Add some references about O-RAN.

Reviewer 2 Report

Comments and Suggestions for Authors

The authors of this paper present a forward-looking perspective on
the future of telecommunications infrastructure, based on the comprehensive examination of the advancements in Cloud- RAN and the integration of AI for resource management within the context of 6G wireless networks. They present and analyse the current state of CRAN, identify significant challenges, and propose AI as a pivotal solution for overcoming these obstacles, thereby enhancing network efficiency, spectrum utilization, and energy conservation. Their discussion extends to the evolution of 6G networks, emphasizing the necessity for intelligent, dynamic resource management to meet the increasing demands of futuristic
applications and services. Finally, the authors contribute to the academic and industrial fields by offering a detailed taxonomy of CRAN resource management and shedding light on the potential of AI to revolutionize 6G networks through improved performance and sustainability.

This is a very well written survey paper, quite well organized and presented. The only concern of the reviewer is the fact that some minor syntax/grammatical errors appear in the paper which should be corrected prior to its acceptance.

Comments on the Quality of English Language

Minor editing is necessary.

Author Response

Thank you very much for taking the time to review this manuscript. 

Reviewer 3 Report

Comments and Suggestions for Authors

The paper itself is interesting, but there are a few things that need to be corrected. 1.

1. Abbreviations and generic terms are used repeatedly. For example, CRAN, C-RAN, and other expressions are not correct and should be unified. 2.

2. A list of abbreviations and generic names should be made. 3) Since this is a survey paper, the number of references should be consistent.

3. since this is a survey paper, the number of references seems to be small. The following are examples, all of which should be added to the Survey of this proposed paper.

- The following are the references on the results of the O-RAN environment in the field.

[1] J. Nakazato, Mitsuhiro Kuchitsu, Anil Pawar, Soh Masuko, Keishi Tokugawa, Keiichi Kubota, Kazuki Maruta, Kei Sakaguchi, "Proof-of-Concept of Distributed Optimization of Micro-Services on Edge Computing for Beyond 5G," 2022 IEEE 95th Vehicular Technology Conference: (VTC2022-Spring), Helsinki, Finland, 2022 Helsinki, Finland, 2022, pp. 1-6, doi: 10.1109/VTC2022-Spring54318.2022.9860668.

- This paper evaluates the 5G testbed.

[2] Xu, D., Zhou, A., Zhang, X., Wang, G., Liu, X., An, C., Shi, Y., Liu, L., Ma, H.: Understanding operational 5G: A first measurement study on its coverage, performance and energy consumption. In:. Proceedings of the Annual Conference of the ACM Special Interest Group on Data Communication on the Applications, Technologies, Architectures, and Protocols for Computer Communication, pp. 479-494 (2020)

5. I wonder if the 6G service scenario in Figure 1 is really correct, and whether it should be considered in the same vein as the eMBB, URLLC, and mMTC proposed for 5G should be debated. A little more analysis of the communities already being considered for 6G should be added.

6. CRAN is discussed as a topic, but since CRAN has been discussed since 4G, it is unclear what the contribution of this paper is. Please explain more clearly.

7. The content of the text in the Related Works section is thin, so please increase the amount of text and the number of references.

8. The structure of this paper is very difficult to read, so please add a figure showing the overall structure.

Comments on the Quality of English Language

Please see above comments.

Author Response

Thank you very much for taking the time to review this manuscript. 

I made the following:

1. Modified Figure 1 to meet requirements and services of 6G.
2. Remove the so-called typos and unified the abbreviations.
3. Add some references about O-RAN.
4. I take the cloud RAN as one of the major interesting networks in upcoming wireless networks and their objectives, constraints and how the Artificial Intelligent and federated learning can lead to O-RAN.

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

Thank you for the modification. I would like to add a few things.

1. Please add the List of abbreviations and generic names in the Table. 

2. Please modify the title. The current title does not match content such as Wave. 

3. I still do not understand the contribution of the paper and the challenge of previous works. It's just an investigative paper. Please add more the discussion parts. 

Comments on the Quality of English Language

N/A

Author Response

Author Response:

First, we would like to express my thankfulness to the editor and the anonymous reviewers for their valuable suggestions and valuable comments which enhance the quality of my work out. In the revised version, I have addressed all the editor and reviewers’ concerns and comments clearly, where my revision is corrected. In this response report, I will present one-to-one responses to individual comments.

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1. Please add the List of abbreviations and generic names in the Table. 

Author Response:

We added it in the end of article before references. (Done!)

 

2. Please modify the title. The current title does not match content such as Wave. 

Author Response:

We suggested title of our article to be (Towards 6G Technology: Insights into Resource Management for Cloud RAN Deployment). I hope that it is appropriate now. (Done!)

3. I still do not understand the contribution of the paper and the challenge of previous works. It's just an investigative paper. Please add more the discussion parts. 

Author Response:

We added a discussion part (section 6) about types of simulators that can be used for simulated 5G and beyond 5G (6G) mobile networks so this article make a comprehensive survey about the most common network infrastructure of CRAN and their objectives, constraints, optimization methods, simulators and how AI can improve the management of resources in it. (Done!)

Author Response File: Author Response.pdf