A Multi-Ray Channel Modelling Approach to Enhance UAV Communications in Networked Airspace
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsTo enhance UAV communications in networked airspace, this paper presents a multi-ray channel model that captures the complexities of the airspace network. The work is commendable, but I have the following concerns:
- Page 14: In the derivation of the path difference (Δxk) and phase difference (ΔÏ•k), the truncation of the Taylor series (retaining only the first two terms) lacks justification.
Suggestion: Supplement the analysis to demonstrate that the higher-order terms can be neglected.
- Page 17, Table 1 Issue: The transmission power is set at -2.14 dBm. Is this parameter set too low?
- The text exhibits redundancy in the expression of parameters. For instance, in the sentence "using parameters K=200 K=200 and d=3 m d=3m", the values for K and d are unnecessarily repeated, which can confuse readers and detract from the text's professionalism. It is recommended to revise the sentence to "using parameters K=200 and d=3 m" to eliminate the redundancy and enhance clarity.
- The description on page 15 indicates that Figure 6 shows an analysis of the relationship between received power and height in G2A and A2A communication environments. However, the title of Figure 6 refers to "the impact of increasing the number of aircraft on received power in G2A and A2A communication link scenarios with K=200 and ds=3m." It is suggested that the title be revised to align with the description provided on page 15. A more appropriate title would be "Analysis of the Relationship Between Received Power and Height in G2A and A2A Communication Environments with K=200 and ds=3m."
- The description on page 20 indicates that Figure 8 presents a comparison of received power with different numbers of UAVs in G2A and A2A communication scenarios. However, the title of Figure 8 refers to "the impact of increasing receiver height on received power in G2A and A2A communication link scenarios with K=200 and ds=3m." It is suggested that the title be revised to align with the description provided on page 20. A more appropriate title would be "Comparison of Received Power With Different Numbers of UAVs in G2A and A2A Communication Scenarios with K=200 and ds=3m."
Author Response
Comment No. 1:
Page 14: In the derivation of the path difference (Δxk) and phase difference (ΔÏ•k), the truncation of the Taylor series (retaining only the first two terms) lacks justification.
Reply:
We sincerely thank the reviewer for highlighting this important point, which indeed adds clarity and depth to the manuscript for the benefit of the reader. To address this point, we have now included a brief explanation in the revised manuscript (Page 14). In general, the third and higher-order terms in the Taylor series expressions are ignored because these terms are negligibly small under the assumed conditions and their contributions do not enhance accuracy of the model. Instead, inclusion of higher-order terms adds complexity without practical benefit and makes the expression cumbersome.
The following text and expressions have been added to the revised manuscript.
|
(16) |
By simplifying Eq (16) further, Eq (17) is written as
(17)
By applying Taylor series Eq (17) and taking the first two terms; we acquired Eq (18) as.
|
Since the higher terms involves , and so on, the higher terms can be truncated after 2nd term, if This implies This condition, that, if and are close i.e., , then is small and the approximation is only valid for very small value of However, if are far apart, then , then, the higher order terms become negligible. Hence, by ignoring higher order terms, the expression becomes, The phase difference for reflected rays is given by Eq (19). (19) By substituting the value of in Eq (19) and the modified equation is in Eq. (20). (20) |
(18) |
Comment No. 2:
Page 17, Table 1 Issue: The transmission power is set at -2.14 dBm. Is this parameter set too low?
Reply:
We highly appreciate the reviewer for pointing out this typo mistake. Upon review, we have found that the transmission power value was mistakenly typed as –2.14 dBm instead of correct value is –22.14 dBm, which reflects the intended low-power transmission scenario applicable to short-range UAV communications. This value was chosen to align with similar settings used in energy-efficient and interference-sensitive applications.
The correction has been made in Table 1 (Page 17), and the text has been updated accordingly to avoid any confusion. We appreciate the reviewer’s attention to detail, which helped us identify and correct this error.
Comment No. 3:
The text exhibits redundancy in the expression of parameters. For instance, in the sentence "using parameters K=200 K=200 and d=3 m d=3m", the values for K and d are unnecessarily repeated, which can confuse readers and detract from the text's professionalism. It is recommended to revise the sentence to "using parameters K=200 and d=3 m" to eliminate the redundancy and enhance clarity.
Reply:
We sincerely thank the reviewer for a detailed review to improve the overall quality and clarity of the manuscript. The highlighted sentences are carefully revised and corrected wherever necessary.
Comment No. 4
The description on page 15 indicates that Figure 6 shows an analysis of the relationship between received power and height in G2A and A2A communication environments. However, the title of Figure 6 refers to "the impact of increasing the number of aircraft on received power in G2A and A2A communication link scenarios with K=200 and ds=3m." It is suggested that the title be revised to align with the description provided on page 15. A more appropriate title would be "Analysis of the Relationship Between Received Power and Height in G2A and A2A Communication Environments with K=200 and ds=3m."
Reply:
We sincerely appreciate the reviewer for this valuable suggestion. We agree with the reviewer that the proposed title of Figure 6 more accurately reflects the content and description on page 15. The title of Figure 6 is revised and changed as “Analysis of the relationship between received power and height in G2A and A2A communication environments with K=200 and ds=3m.”
The following modification has been made to the title of Figure 6 of the revised manuscript.
Figure 6. Analysis of the relationship between received power and height in G2A and A2A communication environments with K=200 and ds=3m.
Comment No. 5
The description on page 20 indicates that Figure 8 presents a comparison of received power with different numbers of UAVs in G2A and A2A communication scenarios. However, the title of Figure 8 refers to "the impact of increasing receiver height on received power in G2A and A2A communication link scenarios with K=200 and ds=3m." It is suggested that the title be revised to align with the description provided on page 20. A more appropriate title would be "Comparison of Received Power With Different Numbers of UAVs in G2A and A2A Communication Scenarios with K=200 and ds=3m."
Reply:
We acknowledge the efforts of the reviewer for a detailed review to improve the quality of the manuscript. We agree with the suggestion of the reviewer to revise the title of Figure 8. The revised title would provide more clarity and align with the description on page 20.
The following change has been made to the title of Figure 8 of the revised manuscript.
Figure 8. Comparison of received power with different numbers of UAVs in G2A and A2A communication scenarios with K=200 and ds=3m."
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe article submitted for review addresses an important topic, which is interference occurring in communication during UAV operations. The aim of the work is to explore the dynamics of UAV communication, investigate the impact of multipath interference on network efficiency and propose opportunities for improved operating reliability across various application fields.
In the first part of the work, the authors thoroughly discussed literature sources that address similar topics. In Chapter 4, the authors referred to the previously discussed literature by assessing aspects of model matching (lines 563-570).
In my opinion, however, there is a lack of clear reference to other issues and a comparison of the obtained solution with solutions proposed by other authors (discussion of results). Especially with such a thorough literature review.
Additionally, in Figures 4-10, the axis descriptions and the legend are not very clear and appear to be of poor quality.
Author Response
General statement by the reviewer:
The article submitted for review addresses an important topic, which is interference occurring in communication during UAV operations. The aim of the work is to explore the dynamics of UAV communication, investigate the impact of multipath interference on network efficiency and propose opportunities for improved operating reliability across various application fields.
In the first part of the work, the authors thoroughly discussed literature sources that address similar topics. In Chapter 4, the authors referred to the previously discussed literature by assessing aspects of model matching (lines 563-570).
Reply:
We thank the reviewer’s thoughtful and encouraging comments. We appreciate the reviewer’s recognition of the literature review and its integration with our modeling efforts. Our intent was to build a d solid foundation by referring relevant work in the literature and then critically evaluate how our proposed model aligns with the existing approaches. We believe this integration enhances contextual and technical depth of the manuscript.
Comment No. 1
In my opinion, however, there is a lack of clear reference to other issues and a comparison of the obtained solution with solutions proposed by other authors (discussion of results). Especially with such a thorough literature review.
Reply:
We thank the reviewer for a valuable comment. We agree that additional issues and comparisons could further enhance the discussion, however, our focus has been on the most relevant and recent studies closely related to our objectives. We acknowledge that discussion and comparison can be further expanded including more articles and detailed comparisons. However, it would significantly increase the length of the manuscript potentially making it difficult for a reader to maintain interest.
Comment No. 2
Additionally, in Figures 4-10, the axis descriptions and the legend are not very clear and appear to be of poor quality.
Reply:
We acknowledge the valuable contribution of the reviewer. Axis descriptions and image quality have been improved in the revised manuscript
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsNo further Comments.
