Sum Rate Maximization for Intelligent Reflecting Surface-Assisted UAV-Enabled NOMA Network
Round 1
Reviewer 1 Report
Comments for author File: 
Comments.pdf
Author Response
Thank you for your insightful comments ，please see the attachment.
Author Response File: Author Response.pdf
Reviewer 2 Report
A NOMA transmission scheme was proposed. The analysis and description of the scheme is clear. Maybe IRS model can affect the performance of the proposed scheme, but it is simplified in the paper. It can be described in more detail. And some citations can be referred for important equations such as (1) ~ (4).
Author Response
Thanks for your comments, please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
I have two major issues with this paper.
The first issue is in terms of the novelty, the authors claim in lines 85-87 that the literature on UAV assisted IRS NOMA is not sufficient, however, with a quick google search i could find the following papers, which have not been cited by the authors:
[1] On the Performance of IRS-Aided UAV Networks With NOMA (2022)
[2] Toward Ubiquitous and Flexible Coverage of UAV-IRS-Assisted NOMA Networks (2022)
[3] Resource Allocation and 3D Trajectory Design for Power-Efficient IRS-Assisted UAV-NOMA Communications (2022)
[4] Intelligent Reflecting Surface Enhanced Multi-UAV NOMA Networks (2021)
All of which deal with the interplay of IRS and UAV in NOMA communications. The authors must address relevant literature and clearly state how their work is novel with respect to these works. As it is, the novelty of this work is lacking when compared to what is present in the literature.
The second major issue i have with the paper is the scenario chosen. It is depicted both in figure 1 and again figure 2, and it shows the following multihop link: BS->IRS->UAV(relay)->UEs.
My main concern here is the choice of this scenario, how likely is it that a UAV that can fly above the skyline of a city, has an impaired channel towards the BS thus needing the presence of the IRS? To me this scenario is remote at best, the presence of the IRS is superfluous, maneuvering the UAV to achieve LOS link with BS would be the best approach.
In lines 216-218 The authors justify the IRS by considering that it is a moving IRS and not a static one, this claim overlooks several technical issues in my opinion. How is the IRS moving? Is it mounted on a rover? Is it another UAV?
It may be just my opinion but the scenario considered does not seem practical. One can compare this scenario to the ones proposed in the papers I previously mentioned: in [1-2] the authors consider IRSes mounted ON the UAVs, which has the benefit of putting a light weight and much less energy hungry device on a constrained UAV, while in [3-4] the scenarios consider networks between UAVs and IRSes mounted on the ground which the UAVs use to increase their coverage.
Otherwise the paper is well written, with minor editing, and has good technical rigour. It uses the ITU method for LoS probability derivation and follows a well established approach calculating outage with the standard PL(LoS)*P(LoS)+PL(NLoS)*P(NLoS).
Several minor modifications to improve the readability of the paper are required:
In the keywords, ariel->aerial.
Line 19: its->their
Lines 100-110, the points (i) (ii) (iii) are not capitals but (IV) is, choose either all capital or all not capital.
Line 130, the acronym SIC is not defined
Line 184, what does "comprehensive consideration(11)(12)" mean? It is not clear.
Line 227-231, this sentence is too convoluted and difficult to understand.
Line 312, you can use SNR instead of signal-to-noise ratio since you have defined the acronym.
Section 6 can be removed.
Author Response
Thanks for your comments, please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments for author File: Comments.pdf
Author Response
Please see the attachment
Author Response File: 
Author Response.docx
Reviewer 3 Report
I have reviewed the modifications the authors have performed in response to my comments as well as their response letter.
The authors have provided sufficient justification and rationale for their scenario as well as a reference that further confirms the validity of the scenario.
Furthermore, regarding the relevant literature the authors have introduced the suggested papers and provided a brief analysis to explain the validity of their contribution against those already present.
I have no further suggestions, the paper can be accepted in present form.
Author Response
Thank you for your recognition. Your insightful comments and suggestions have significantly improved the quality and clarity of our manuscript. We will continue to improve our research.
