On IRS-Assisted Covert Communication with a Friendly UAV

Round 1

Reviewer 1 Report

Summary/Contributions: This work proposes an intelligent reflecting surface (IRS)-assisted covert communication system (CCS) using a friendly unmanned aerial aircraft (UAV) that makes artificial noise (AN) to confuse monitors. Traditional wireless covert communication technologies struggle in densely populated cities with high-rise structures. The research models the UAV's AN power as an uncertainty model and derives a closed-form DEP on the monitor's covert wireless transmission. The paper formulates an optimization problem to maximize the covert rate based on the DEP and designs a Dinkelbach-based iterative algorithm to solve it. The simulation results show that the proposed system achieves the highest covert rate when the IRS unit phase, trajectory, and UAV transmit power are tuned.


Comments/Suggestions:
1. Provide a more detailed overview of the existing literature on covert communication systems, including different approaches and their limitations. This would help to contextualize the proposed approach and highlight its novelty.

2. Discuss the potential security risks and vulnerabilities of the proposed approach, including potential attacks by adversaries and the limitations of the jamming technique used to reduce detection rates.

3. Provide more information on the system model, including the specific parameters and assumptions used, and how they affect the performance of the proposed approach.

4. Discuss the potential practical applications of the proposed approach, including scenarios where covert communication is necessary, and how the proposed approach could be deployed in real-world settings.

5. Provide more information on the optimization problem formulation and the iterative algorithm used to solve it, including any potential limitations or challenges in the optimization process.

6. Discuss the scalability of the proposed approach, including how it could be extended to handle larger and more complex communication networks.

7. Provide a more detailed evaluation of the simulation results, including a sensitivity analysis of key parameters and a comparison with existing methods.

8. Discuss the potential limitations and challenges in implementing the proposed approach in practice, including issues related to hardware and software compatibility, regulatory requirements, and cost-effectiveness.

9. The authors need to add a short paragraph about the security aspects of drone communications.   10. For this purpose, they may include the following references (and others) in their study:    a. https://ieeexplore.ieee.org/document/9842403    b. https://www.mdpi.com/1424-8220/21/6/2057

Can be improved.

 

Author Response

Dear reviewer,

We are writing to you to submit a revised version of the paper with Manuscript ID  drones-2450936. We would like to thank you for the comments on the previous manuscript. We have carefully addressed the comments from you. The details can be found in the remainder of this document. In the revised manuscript, we have also colored  in blue  the revised parts.

All the response to the conmments please see the attached file, thanks.

Sincerely,
The Authors      

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear Authors,

                 As IRS has emerged as a very hot topic so presented article is a good contribution in this domain. The research design is appropriate and system model is clearly described. I do not have any specific comments, but you can consider.

1. Please define UAV at the first place of appearance in the Abstract. You can also check other abbreviations.

2. Line 48, please list a few adversaries to make it clear. 

3. Introduction is well presented and discussed with proper reference literature. 

4. It will be interesting to add some discussion about IRS and UAV integration and advantages of this coexistence. 

5. System model and optimization approach is clearly described. 

6. To reduce the computational complexity, authors have used SCA algorithm, any specific advantages or any other suitable approach for better results.

7. System design parameters and numerical results are well explained. 

8. A future research aspect based on current findings must be added in the Conclusion. 

9. A few references are outdated. overall, references are relevant and updated to support this research contribution.  

Dear Editor,

The English writing is fine. The authors should pay attention to abbreviation and define at the first place of appearance. 

Author Response

Dear Reviewer,

We are writing to you to submit a revised version of the paper with Manuscript ID  drones-2450936. We would like to thank you for the comments on the previous manuscript. We have carefully addressed the comments from you. The details can be found in the remainder of this document. In the revised manuscript, we have also colored  in blur the revised parts.

All the reponse of your comments please see the attached file, thanks!

Sincerely,
The Authors      

Author Response File: Author Response.pdf

Reviewer 3 Report

 

This paper proposes an IRS-UAV assisted covert communication system to improve the covert rate. the closed-form detection error probability (DEP) on the covert wireless communication is derived. The optimization problem to maximize the covert rate is resolved by an iterative algorithm using Dinkelbach method. The topic of this paper is interesting and of practical importance. The whole paper is well written and organized. I still has the following problems.

1. In the simulation results, authors’ proposed scheme can achieve better performance. However, the proposed scheme jointly integrates several methods. Please clarify the main contributions/novelty of the proposed method.

2. The proposed algorithm in Section 4.4 should be given in advance, such that the reader can understand the iterative algorithm to solve the sub-problems.

3.For the system model, only one Bob and Wille are considered, how about the more users?

4. there are recently published paper on multi-user communcation, please describe in introducation. 

5. Furthermore, for the optimization problem, we generally consider the case that multiple antennas are used at the base station, while the single antenna for users.

 

 

Author Response

Dear reviewer,

We are writing to you to submit a revised version of the paper with Manuscript ID  drones-2450936. We would like to thank you for the comments on the previous manuscript. We have carefully addressed the comments from you. The details can be found in the remainder of this document. In the revised manuscript, we have also colored  in blue the revised parts.

All the reponses to your comments please see the attached file, thanks.

Sincere

The authors

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors considered my comments and suggestions. Good luck.

May be improved.