A Critical Examination of the Beam-Squinting Effect in Broadband Mobile Communication: Review Paper

Round 1

Reviewer 1 Report

Please see the attached file.

Comments for author File: Comments.pdf

Author Response

Reviewer 1

Comments to electronics-2040237 This paper provided an overview on the topic of beam squint and how it might be alleviated while also minimizing the complexity and expense of hardware implementation. Honestly, the authors have provided a comprehensive review of beam squinting. However, some parts are not clear, and both the motivations and contributions should be further clarified. The reviewer has the following concerns:

1. The abstract is not well written, too much content focus on the background and facing challenges, and the introduction of this paper is not sufficient enough.

Thank you, the whole abstract is revised accordingly, we have also extended the introduction section 1.

2. The authors should unify the writing of some commonly used words, such as “mm-wave”, “mm-Wave” and “MmWave”, and the above abbreviation is not introduced. It is suggested to use mmWave as the abbreviation of millimeter wave.

Thank you, we have unified most of the abbreviation suggested by the reviewer.

3. The authors should check the whole paper to avoid the symbols before the references, such as “deliver. [2].”, “bottleneck. [3].”, “available. [11].”, “direction. [15].”

Thank you, the whole paper has been revised and checked to suit this comment.

4. Both the motivations and contributions of this paper are not referred in this paper, which need to be justified.

Thank you, based on this comment, we have revised the main motivations and contributions of the present work over most of the sections. Please refer to the revised version of the paper.

5. As a review paper, the introduction of existing work is not sufficient. It is suggested to introduce the following recent works [R1]-[R4] in mmWave communications field to highlight the state-of-the-art of this paper.

Thank you, the purpose of our paper is to provide a critical review of a beam squint problem in broadband mobile communication, so we add two (R1 and R3) of the suggested references which we think they related to the subject of our current work.

[R1] “Refracting RIS aided hybrid satellite-terrestrial relay networks: Joint beamforming design and optimization,” IEEE Transactions on Aerospace and Electronic Systems, vol. 58, no. 4, pp. 3717-3724, Aug. 2022.

 [R2] “SLNR-based secure energy efficient beamforming in multibeam satellite systems,” IEEE Transactions on Aerospace and Electronic Systems, early access, Jul. 2022, doi: 10.1109/TAES.2022.3190238.

[R3] “Joint beamforming and power allocation for satellite-terrestrial integrated networks with non-orthogonal multiple access,” IEEE Journal of Selected Topics in Signal Processing, vol. 13, no. 3, pp. 657-670, June 2019.

 [R4] “Supporting IoT with rate-splitting multiple access in satellite and aerial-integrated networks,” IEEE Internet of Things Journal, vol. 8, no. 14, pp. 11123-11134, Jul. 2021.

6. The figures 2-4 too blurry to figure out, besides, the figure 10 also looks strange. All the figures look like screenshot from other’s works, instead of drawing or simulating by authors, which should be improved.

Thank you, we have approved all figures in the revised version accordingly.

 

Reviewer 2 Report

The topic of this review article is very interesting and it will be a good contribution if the authors completely revise it to overcome several serious concerns. English writing is fine. However, there is a complete lack of presentation quality and organization in this study. There are several major concerns that authors must address:

1.     Both abstract and conclusion must be revised. Authors should rewrite to make it more attractive and meaningful for readers.

2.     For English writing, I suggest carefully revising the entire manuscript to overcome writing flow and enhance quality.

3.     Introduction section requires more reference literature and sufficient discussion.

4.     Where is the organization of this study? Missing, so the authors should add it to the end of the introduction section.

5.     In the start of each section, please provide a short summary to introduce each section.

6.     It is highly recommended to provide a Table to evaluate your research contributions by comparing with existing reviews or surveys.

7.     MIMO, 5G, LOS, etc. are not fully defined in the first place of appearance. Abbreviations must be defined at the first place of appearance in the manuscript.

8.     The resolution quality of figures is extremely bad. Even text written within figures is not readable. All figures must be provided with high resolution for better readability.

9.     Even though Table 1 is nicely presented, but there is a lack of tables in this study.

10.                        Section 2 requires a more comprehensive discussion and reference literature.

11.                        It is suggested that authors should draw some nice figures rather than copying from all references.  

12.                        Some figures require proper discussion such as Figures 7 and 8 are given without detailed explanation.

13.                         Section 3 requires a comparison table. Reference literature is fine.

14.                         Carefully check figure 15, there are 4 parts in the presented figure but there is no discussion and description of each part, why?

15.                        For reference section: I suggest adding more relevant studies from recent 5 years.

Author Response

Reviewer 2

The topic of this review article is very interesting and it will be a good contribution if the authors completely revise it to overcome several serious concerns. English writing is fine. However, there is a complete lack of presentation quality and organization in this study. There are several major concerns that authors must address:

1. Both abstract and conclusion must be revised. Authors should rewrite to make it more attractive and meaningful for readers.

Thank you, we have revised the whole abstract and conclusions sections accordingly.

2. For English writing, I suggest carefully revising the entire manuscript to overcome writing flow and enhance quality.

Thank you, the paper has been revised by an English native.

3. Introduction section requires more reference literature and sufficient discussion.

      Thank you, the introduction section has been revised accordingly.

4. Where is the organization of this study? Missing, so the authors should add it to the end of the introduction section.

Thank you, the organization of the paper has been added to the end of the introduction section.

5. In the start of each section, please provide a short summary to introduce each section.

Thank you, we have tried our best to address this comment in the revised version of the manuscript.

6. It is highly recommended to provide a table to evaluate your research contributions by comparing with existing reviews or surveys.

Thank you, the current work is just a critical explanation of the work for a number of researchers on the topic of beam squint, we didn’t find a similar review in this field.

7. MIMO, 5G, LOS, etc. are not fully defined in the first place of appearance. Abbreviations must be defined at the first place of appearance in the manuscript.

Thank you, all Abbreviations have been revised and defined at the first place of appearance in the manuscript. 

8. The resolution quality of figures is extremely bad. Even text written within figures is not readable. All figures must be provided with high resolution for better readability.

Thank you, all figures have been approved accordingly.       

9. Even though Table 1 is nicely presented, but there is a lack of tables in this study.

Thank you, we have added another table in Section 3 to address this comment.    

10. Section 2 requires a more comprehensive discussion and reference literature.

Thank you, we have added the discussions to section 2 accordingly.     

11. It is suggested that authors should draw some nice figures rather than copying from all references. 

Thank you, all figures were approved in the revised manuscript.

12. Some figures require proper discussion such as Figures 7 and 8 are given without detailed explanation.

Thank you, a brief discussion of figures 7 and 8 has been added.       

13. Section 3 requires a comparison table. Reference literature is fine.

Thank you, we have added a comparison table in this section. Please refer to the revised manuscript.

14. Carefully check figure 15, there are 4 parts in the presented figure but there is no discussion and description of each part, why?

      Thank you, a discussion of figure 15 and a description of each part have been added in the revised version of the paper.        

15.  For reference section: I suggest adding more relevant studies from recent 5 years.

Thank you, two new references have been added.  

 

Reviewer 3 Report

The paper presents a review of the research regarding beam squint as well as the attempts made for either its alleviation or its utilization and, in any case, for the reduction of the hardware’s complexity and cost.  

Comments

The paper will be examined as a review one and not as an original contribution to the relevant research.

I think that the main weakness of the paper is that, though the review made is thorough and informative, it does not refer almost at all to possible future research on the topic. A relevant reference made in lines 537-540 is very short and not at all specific.

I suggest the authors to add a section presenting their attitude towards future developments on the topic.

Relevant to the above comment, is the fact Section “5. Conclusion” is rather short for this kind of paper and compared to the rest of the text. I suggest it should be made more detailed (including a reference to future work on the field following the addition of a relevant section).

The paper needs editing regarding the use of English.

My reviewing decision is that the paper is publishable subject to the comments made above and provided the Journal is willing to publish it as a review paper (and not an original contribution to the relevant research).   

Author Response

Reviewer 3

The paper presents a review of the research regarding beam squint as well as the attempts made for either its alleviation or its utilization and, in any case, for the reduction of the hardware’s complexity and cost.  

Comments

The paper will be examined as a review one and not as an original contribution to the relevant research.

Response) Thank you, yes it is a review paper that stated the tradeoff between the effect of the squint beam in antenna arrays and the complicity of the hardware to compensate for this effect. We have tried to address the main contributions in terms of the methodologies that were applied in mmwave communications systems.  

 

I think that the main weakness of the paper is that, though the review made is thorough and informative, it does not refer almost at all to possible future research on the topic. A relevant reference made in lines 537-540 is very short and not at all specific.

Response) Thank you, a more detailed discussion has been added for such references. Please refer to the revised version of the manuscript.

 

I suggest the authors to add a section presenting their attitude towards future developments on the topic.

Response) Thank you, we have added a new table 1 in section 3 and revised the whole conclusions section to reflect our response to this comment.

 

Relevant to the above comment, is the fact Section “5. Conclusion” is rather short for this kind of paper and compared to the rest of the text. I suggest it should be made more detailed (including a reference to future work on the field following the addition of a relevant section).

Response) Thank you for this comment, we have revised the whole conclusion section and added a more detailed discussion to support our response to this comment.

 

The paper needs editing regarding the use of English.

Response) Thank you, the paper has been revised by an English native accordingly.

 

My reviewing decision is that the paper is publishable subject to the comments made above and provided the Journal is willing to publish it as a review paper (and not an original contribution to the relevant research).   

Response) Thank you for your interest and encouragement, we have done our best to address the comments, and we are happy to accept your suggestion as a review paper.

 

 

Round 2

Reviewer 1 Report

Although the authors basically addressed my concerns, however, the figures are still blurry which should be redrwan instead of a simple screenshoot, beside, some references are lack of the authors names, such as [65] and [67].

Furthermore, an advanced technique, called RIS [R1], which would suppress the Beam-Squinting Effect in Broad band Mobile Communication, should be introduced to make the review more comphrehensive.

[R1] “Joint beamforming design for secure RIS-assisted IoT networks,” IEEE Internet of Things Journal, early access, Sep. 2022, doi: 10.1109/JIOT.2022.3210115.

Author Response

Reviewer 1:

Although the authors basically addressed my concerns, however, the figures are still blurry which should be redrwan instead of a simple screenshoot, beside, some references are lack of the authors names, such as [65] and [67].

Response) Thank you, all figures have been approved in the revised manuscript. The details of the two references have been added as well.

 

Furthermore, an advanced technique, called RIS [R1], which would suppress the Beam-Squinting Effect in Broad band Mobile Communication, should be introduced to make the review more comphrehensive.

[R1] “Joint beamforming design for secure RIS-assisted IoT networks,” IEEE Internet of Things Journal, early access, Sep. 2022, doi: 10.1109/JIOT.2022.3210115.

Response), Thank you, this reference is also added to the list of references.  

Reviewer 2 Report

Dear authors,

Thank you for your efforts. Even though the quality of the revised draft is much better. However, you must improve the quality of Figures 1, 3, 7, 8, 11 and 13.  In addition, LOS stands for line-of-sight, while you have written line of site in line 88. In line 409, you have written None Line of Site (NLoS), which should be Non-line-of-sight. I have noticed several English writing and format issues. You must carefully revise and overcome these issues.  

Author Response

Reviewer 2

Thank you for your efforts. Even though the quality of the revised draft is much better. However, you must improve the quality of Figures 1, 3, 7, 8, 11 and 13.  In addition, LOS stands for line-of-sight, while you have written line of site in line 88. In line 409, you have written None Line of Site (NLoS), which should be Non-line-of-sight. I have noticed several English writing and format issues. You must carefully revise and overcome these issues.  

Response) As requested, the new manuscript features enhanced versions of all previously presented figures. We updated the acronyms to reflect the new terminology.

Reviewer 3 Report

I am happy with the modifications made by the authors and my suggestion is the paper to be published as a review one.

My overall recommendation ("Accept after minor revision") has to do with a minor editing regarding the use of English which I think is still necessary.  

Author Response

I am happy with the modifications made by the authors and my suggestion is the paper to be published as a review one.

My overall recommendation ("Accept after minor revision") has to do with a minor editing regarding the use of English which I think is still necessary. 

Response) thank you for your recommendations, we have tried our best to improve the reading style of the paper.