Supporting Global Communications of 6G Networks Using AI, Digital Twin, Hybrid and Integrated Networks, and Cloud: Features, Challenges, and Recommendations

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1. Some assumptions lack theoretical support, such as those presented in lines 241-245 and 259-263. It is suggested to add literature references to prove them.
2. There are inconsistencies in the reference format in the paper, such as in 43 and 44.
3. Although the paper presents multiple forward-looking discussions and technical prospects on 6G networks, it lacks in-depth analysis and actual data support in some parts. For instance, while the challenges of 6G networks are mentioned, no relevant experimental data or model predictions are provided to support these viewpoints.
4. There is a period after "6G" in line 133
5. It is recommended to enlarge the font in Figures 4 and 6 to the same size as the font in Figure 7
6. It is suggested to unify the "technical objectives" in line 107 with the "Emerging topics" in line 227, either using Roman numerals or abcd, and to wrap each point in a new description.
7. The points in the "Detailed explanations" section of line 333 are recommended to be consistent with the previous text, either using Roman numerals or abcd or first, second... It is also suggested to wrap each point in a new description.
8. The image and caption in Figure 8 are separated by a page
9. It is recommended not to use blue and green backgrounds with black text in Figure 9, as it is not easy to see clearly
10. The abbreviation table is incomplete and some abbreviations are not provided, such as LEO satellite (Low Earth Orbit, LEO), UAV (Unmanned Aerial Vehicle), QoS (Quality of Service), etc. It is also recommended to arrange the abbreviation table in alphabetical order
11. Section 3.2 suggests dividing the description into sections according to Table 3. If it is too long, it may appear illogical and difficult to distinguish between different challenges

Author Response

Thanks for all the comments. Please check the attached file.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Overall evaluation
This article systematically explores the potential technical architecture, core challenges, and future research directions of 6G networks, covering key technologies such as artificial intelligence (AI), digital twins (DT), hybrid networks (RF/optical communication), and cloud computing. The paper has a clear structure and a comprehensive literature review, providing valuable insights into the technical requirements and application scenarios of 6G. However, some of the content lacks theoretical depth, technical challenge analysis lacks specific solutions, and the timeliness of literature needs to be strengthened, which require further modification and improvement.
Main advantages
Timeliness of research topic: As a cutting-edge direction in the field of communication, 6G has high academic value and practical significance in the selection of research topics, especially in providing new perspectives on the integration of AI and digital twins.
Structural integrity: The paper is logically clear, starting from the limitations of 5G and gradually expanding on the requirements, challenges, and suggestions of 6G technology. The chapter connections are reasonable.
Literature coverage breadth: AI DT、 The recent research on supporting technologies such as cloud computing has enhanced the credibility of the argument.
Main issues and suggestions
1. Insufficient technological depth and innovation
Problem: The analysis of some technical challenges remains superficial, lacking specific solutions or experimental verification. For example:
Hybrid RF/optical network: Only handover and blocking problems are listed, but no targeted optimization algorithms or simulation results (such as machine learning based dynamic resource allocation) are proposed.
Digital twin network: Although the challenge of real-time modeling is mentioned, how to reduce the computing cost through lightweight models or edge computing is not discussed.
Suggestion:
For key challenges such as channel modeling and energy optimization, supplement specific cases or mathematical models (such as game theory and reinforcement learning frameworks).
Increase discussion on emerging technologies such as terahertz communication and quantum encryption to enhance technological foresight.
2. Timeliness and coverage of literature review
Problem: Some references focus on 2020-2022 and lack the latest research results from 2023-2024 (such as 3GPP Release 18's standardization progress for 6G and the EU's 6G-SNS project dynamics).
Suggestion: Supplement the latest literature in the following directions:
AI driven network slicing (such as IEEE TNSM 2023, "AI based Network Slicing for 6G").
Green 6G technology (such as ITU-R report "Energy Efficiency in 6G Networks", 2023).
3. Lack of methodology and experimental validation
Problem: The paper mainly focuses on reviews, but lacks quantitative analysis of key technologies such as AI algorithm performance comparison and hybrid network throughput simulation.
Suggestion:
Increase simulation experiments or case studies, such as:
Compare the differences in latency and error rate between traditional channel models and AI driven dynamic models.
The numerical simulation shows the optimization effect of edge computing on SAGS network load balancing.
4. Format and language issues
Question:
Some terms are inconsistent (such as the mixing of "LiFi" and "VLC").
The formula and chart numbering are not standardized (such as Figure 1 not cited in the main text).
There is redundancy in language expression (such as repeated emphasis on "rural coverage" in the abstract).
Suggestion:
Unified terminology (such as using "LiFi" instead of "VLC" throughout the article).
Check the chart references and supplement necessary captions (such as the technical methods in Figure 8 that need to be clearly explained).
Simplify the language and remove redundant statements (such as overlapping discussions on AI in sections 1.2 and 3.1).
5. The conclusion section needs to strengthen its contribution and outlook
Problem: The conclusion is relatively vague and does not clearly summarize the unique contributions of this article.
Suggestion:
Extract core innovation points (such as proposing a "dynamic optimization framework for 6G networks based on digital twins").
Clarify future research directions, such as the deep integration of 6G and satellite communication, and the design of privacy protection mechanisms.
Recommended Decision
Revise and re evaluate (Major Revision). The paper needs substantial improvements in technical depth, literature updates, experimental verification, and language expression.

Author Response

Thanks for all comments.

Please check the attached file.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Define the type of paper  (Article, review. etc.).

Review typos in figure 6 "Man-machine".

Review what you want to say in the figure in the caption in figure 13 (row 602).

1. In general, there are several works that deal with various aspects of 6G, which makes your work different from similar ones? In his work in section 3.2 he talks about the problems caused by the roughness of the ocean surface, the signals in the 6 GHz band, which solution proposal could be viable? 
2. Based on the above, the possible alternatives could be analyzed in other problems shown. In his manuscript it is necessary to relate them to 5G operation functionalities with 6G functionalities. 3.
3. On the other hand, a more concise study on what current and emerging technologies could be adapted to 6G would be convenient.
4. Another issue that is not dealt with in depth is that of AI in the context of 6G. Review this factor in your work and explain it in detail. 

Author Response

Thanks for all comments and suggestions.

Please check the attached file and the updated manuscript.

Author Response File: Author Response.pdf