Tradeoff Analysis between Spectral and Energy Efficiency Based on Sub-Channel Activity Index in Wireless Cognitive Radio Networks

Round  1

Reviewer 1 Report

Please find below my comments/suggestions.

Correct all the typo mistakes.

Remove the redundant paragraph of contributions of this paper from Introduction section as it is clearly mentioned in Section 1.2.

Write the physical meaning of the all the equations used in the paper for better understanding of the potential readers.

Provide detail simulation parameters in tabular form. 

What is the drawback of proposed method/system.

List the future work.

Author's Response to Reviewer 1

I would like to thank you for your analysis, which has helped to improve this paper. I think I am not totally good, if there is a concern I am always available to answer. Thank you.

Thanks for the editors’ and reviewers’ comments and suggestions, which really are great help for us to improve our paper presentation. According to the comments of the reviewers, we have revised our manuscript carefully. The revised manuscript and the detailed responses to the comments of the one reviewer are attached. We hope that our revision can meet the comments well. Thank you very much for reviewing my paper. Your comments are very important and help us. The response is as follows:

Question :

-        Correct all the typo mistakes.

-        Remove the redundant paragraph of contributions of this paper from the introduction section as it is clearly mentioned in Section 1.2.

-        Write the physical meaning of all the equations used in the paper for a better understanding of the potential readers.

-        Provide detail simulation parameters in tabular form.

-        What is the drawback of the proposed method/system.

-        List the future work.

Answer :

-        The typo mistakes found in the manuscript are corrected.

-        The contribution part of the introduction section is well organized.

-        The physical meaning and symbols of certain equations are revised in the manuscript.

-        The simulation parameters are shown in Table1 as you requested.

-        The future research topic is presented in the conclusion section.

-        Some details are given in section 5 regarding optimizations formulated

Yours sincerely

Author, Prince SEMBA YAWADA

Reviewer 2 Report

The paper faces an important topic in Cognitive Radio networks, that is the capability to perform several further operations with respect to traditional cellular network, e.g. spectrum awareness, by keeping the energy consumption under constrained levels. Furthermore, energy efficiency must be achieved by taking into account QoS performance indexes, thus not neglecting the spectral efficiency. The idea is interesting and the authors prove how these two constraints can live together and an optimal solution can be found, also considering all power portions due to relay functions and circuitry. However, I have two main concerns: first, the authors should pay attention to all special symbols that are not readable and sometimes this reviewer has read some chinese symbols instead of greater/equal/less mathematical symbols. Second, paper must be restructured to make it readable, because several theoretical derivations are accumulated in the first part and too many simulation results are given together, without allowing the reader to distinguish different contributions. As an example, Figure 2 shows a comparison with PCE, that is not widely explained before and just after it is said to be a reference for the performance to be shown. Therefore, this reviewer thinks that, even if the content is appreciable, not really super new in terms of topic but anyway interesting, the paper has to take a more sistematic structure, symbols must be adequately taken care of and the simulation part has to be restructured and surely better explained, by adding a preliminary section that gives a general framework of what the reader is going to see. Finally, the paper should strongly motivate why the authors' proposal has to be accounted instead of others that are currently available in literature, by enforcing the state of art section (not actually present in the current version).

Author's Response to Reviewer 2

I would like to thank you for your analysis, which has helped to improve this paper. I think I am not totally good, if there is a concern I am always available to answer. Thank you.

Thanks for the editors’ and reviewers’ comments and suggestions, which really are great help for us to improve our paper presentation. According to the comments of the reviewers, we have revised our manuscript carefully. The revised manuscript and the detailed responses to the comments of the one reviewer are attached. We hope that our revision can meet the comments well. Thank you very much for reviewing my paper. Your comments are very important and help us. The response is as follows:

Question :

The paper faces an important topic in Cognitive Radio networks that is the capability to perform several further operations with respect to traditional cellular network, e.g. spectrum awareness, by keeping the energy consumption under constrained levels. Furthermore, energy efficiency must be achieved by taking into account QoS performance indexes, thus not neglecting the spectral efficiency. The idea is interesting and the authors prove how these two constraints can live together and an optimal solution can be found, also considering all power portions due to relay functions and circuitry. However, I have two main concerns: first, the authors should pay attention to all special symbols that are not readable and sometimes this reviewer has read some chinese symbols instead of greater/equal/less mathematical symbols. Second, paper must be restructured to make it readable, because several theoretical derivations are accumulated in the first part and too many simulation results are given together, without allowing the reader to distinguish different contributions. As an example, Figure 2 shows a comparison with PCE, that is not widely explained before and just after it is said to be a reference for the performance to be shown. Therefore, this reviewer thinks that, even if the content is appreciable, not really super new in terms of topic but anyway interesting, the paper has to take a more systematic structure, symbols must be adequately taken care of and the simulation part has to be restructured and surely better explained, by adding a preliminary section that gives a general framework of what the reader is going to see. Finally, the paper should strongly motivate why the authors' proposal has to be accounted instead of others that are currently available in the literature, by enforcing the state of art section (not actually present in the current version).

Answer :

In this manuscript we have brought some correction as you asked:

-        An explanation is given regarding perfect channel operation (PCE) at the beginning of the simulation results section.

-        Some symbols used are changed in the manuscript to allow a good understanding.

-        Certain precisions are made in the manuscript concerning mathematical formulas to allow a good understanding.

-        The simulation part is organized.

-        Some details are given in section 5 regarding optimizations formulated

Yours sincerely

Author, Prince SEMBA YAWADA

Round  2

Reviewer 2 Report

The authors have improved the paper, now the structure is more clear and it is much more readable. Slight modifications in results also contribute to improve the paper. Still unknown symbols are present in the equations. In particular, please be careful to equations: 23, 24, 30,32, 41. They must be corrected, otherwise paper cannot be published with undecoded symbols. 

Finally, in the conclusions, still I missed to read why this approach could be preferred to others working to find a trade-off between EE and SE, and if the approach is optimal or suboptimal.

Author Response

Good day,

We have received your comments regarding our manuscript. We personally want to thank you for your very pertinent remarks that you brought this paper and that also allowed us to improve our paper. We have just taken into account your last remarks concerning the symbols in Chinese characters that were in the equations. Indeed, in the manuscript in Word format, these symbols do not appear but it is at the moment of conversion to PDF that these symbols appear in the equations. But, we have just found a solution to this problem as can be seen in the manuscript. We take the opportunity to send you the manuscript in Word format and in PDF format that you will find attached. Concerning the conclusion part, a small precision has been brought. If you have any questions regarding this manuscript, we are available to answer you.

Best regards