Three-Dimensional Physics-Based Channel Modeling for Fluid Antenna System-Assisted Air–Ground Communications by Reconfigurable Intelligent Surfaces

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper introduces 3-D Physics-Based Channel Modeling for fluid antenna systems, Assisted Air-Ground Communications by configurable intelligent surfaces. Here are my comments

• Why did the authors use 5 GHz in the modeling? If the frequency goes to a higher frequency band, what will happen to the results?
• What about the real implementation of this configuration, especially in fluid antenna, and how it is compatible with compact-sized systems?
• The authors should compare their work with others, so a table of comparison with new references should be added.
• How do the internal fluid movements of the antenna affect the channel stability?
• What about the real implementation of the RIS, which achieves your requirements?

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

1. This paper focuses solely on theoretical interpretation, so a discussion on the possibility of actual implementation is warranted.
(In an actual external environment, the efficiency and performance improvement figures of the proposed communication channel model compared to the existing communication channel model)

2. There is no comparison table with other papers.
There should be a performance comparison of the improvement in performance between the proposed model and other existing papers or technologies.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This paper is a little bit confused, and the things should be better formatted and explained. The main reviewer concerns include,

• The formatting of the paper should be improved. Also, some errors cand be found, e.g. “thre-dimensional” pag. 4 , L145. The paper should be carefully reviewed to fix these issues.
• This paper is related with channel modeling and the title emphasis that, but surprisingly in the related most of references are not related with channel modeling but for RIS in general. For example, the words “channel model” is not used in related work, which is strange given the topic of this work.
• The contributions are not linked with the SoA. What is the main novelty of the contributions related to the SoA? This is not clear since the things are not connected.
• A paragraph in the end of the introduction is missing with the organization of the rest of the paper.
• Fig1 is quite hard to follow since there is a lot of things and some symbols are not defined or discussed in section I.
• Sections 3 and 4 are not presented in the best way. They are confused and hard to follow.

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

1. The introduction should better contextualize the research within the broader scope of 6G wireless communications, particularly the role of reconfigurable intelligent surfaces (RIS) and fluid antenna systems (FAS) in addressing 6G challenges like high-frequency signal blockage and spatial constraints.
2. The manuscript lacks detailed theoretical explanations for key formulas, such as the autocorrelation function and channel impulse responses. Adding derivations or step-by-step explanations would improve readability and rigor. For instance, clarify how the Rician factor dynamically adjusts RIS and NLoS components in Eq. (10).  
3. The choices of parameters in section 5 require detailed justification, such as how RIS dimensions and UGV velocity align with 6G standards or realistic scenarios. Authors should clarify their representativeness.
4. Figures (e.g., Fig. 2) must be improved for clarity, ensuring symbols and curves are easily legible。
5. The paper should provide some future research challenges for RIS-FAS communication systems, such as joint channel estimation, real-time optimization in dynamic environments, and scalability issues.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Most of the comments have been applied and revised.

There are no more review comments for this paper.

Reviewer 3 Report

Comments and Suggestions for Authors

The authors have satisfactory addressed the main reviewer’s comments and the paper is now in good shape to be accepted.