An Improved GreenOFDM Scheme for PAPR Reduction
Round 1
Reviewer 1 Report
In this paper, the author proposed a PAPR reduction scheme for OFDM. The proposed scheme is simple and effective at the same time. The paper is well-organized and easy to follow. However, this reviewer has the following concerns.
- The literature survey needs to be improved. There are tons of papers and algorithms to cope with the PAPR issue in OFDM. Thus, including the representative papers, the author should provide more extensive literature survey and clarify the distinction of their proposed algorithm.
2. The simulation results are not discussed in detail. For each simulation result, the authors need to explain the lessons learned in more detail.
Author Response
The answers to the questions of each reviewer are here presented, organized in chronological order.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This is a nice paper with a small but interesting contribution to the reduction of PAPR in OFDM systems. The results are clearly presented and the paper is very easy to read.
I only have a few suggestions:
- The authors describe their own work as "clever" and "ingenious". I am not personally opposed to an author ranking his/her own work highly, but it can be said that the paper's readers are in the best position to judge the contribution. My suggestion is to remove these adjectives as unnecessary, but I leave it to the editor and authors to decide.
- In the footnote below line 236, it is not clear what the "previous work" is. It might be clearer to include an explicit reference. Also, I think that "are the more representatives" might be replaced by "are the greatest contributors to complexity", or something along those lines.
- I don't understand why the further complexity reduction ideas in section 5.3 are not incorporated into the main results. To me this is the greatest weakness in the paper, and it leaves me with the feeling that the paper is incomplete or only half-done. I encourage the authors to implement these ideas and present even stronger complexity reductions in the main section of the paper.
Author Response
The answers to the questions of each reviewer are here presented, organized in chronological order.
Author Response File: Author Response.pdf
Reviewer 3 Report
The paper, which presents an improvement to a Peak-to-Average-Power-Ratio (PAPR) reduction technique for OFDM proposed by the same authors, is clear and well organized.
My main suggestion regards the numerical results: they are shown correctly for increasing values of the number of sub-carriers but for a single modulation, i.e. QPSK. It would be important to see a couple of similar figures for an M-QAM modulation with higher number of levels, 16 or 64.
Author Response
The answers to the questions of each reviewer are here presented, organized in chronological order.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors addressed this reviewer's comments well. The paper is ready for publication.
Author Response
Dear Editor-in-Chief and Reviewers,
Please find here attached our answers to the minor revisions.
Sicerely,
The authors.
Author Response File: 
Author Response.docx
Reviewer 2 Report
* Regarding the authors' reply to my original comment regarding the use of "clever" and "ingenious": I understand their intent now. There may be a way to say it without sounding self-promoting: for example, "The proposed technique results from tweaks and small improvements to [X]".
* Regarding further complexity improvements, I think that section 5.3 is acceptable, even if the work still feels a little bit incomplete.
* "The man skilled of the art shall notice that the proposed idea tends to PAPR reduction results that are statistically similar to those obtained independently in [29] though the starting point of the presented method is the GreenOFDM scheme. Furthermore, in this work we provide analytical expressions to predict the PAPR for a given configuration which is necessary to correctly dimension some parts of the analog circuitry and for computational complexity reductions [28]."
This paragraph can be made clearer, for example: "The proposed idea results in PAPR reductions that are statistically similar to those in [29]. However, our proposal allows for analytical predictions of the PAPR in a given configuration, which aids the design of the analog front-end [why?], and suggests further complexity reductions [28]."
* In the paragraph below 5.2, I suggest removing "(e.g. p=10^{-3})", since it provides no useful information.
* In Line 200, "These leads us to conclude that the analytical expressions are valid for constellation mappings that are strictly in the unitary circle like the previously analysed QPSK." I believe this is a very weak assertion, since it is at least possible that the discrepancy comes from somewhere else. Is there anything in your analysis that depends on the constellation lying on a circle? I note that in the Conclusions you assert that the approximation requires a "small" constellation, not necessarily one lying on a circle.
Author Response
Dear Editor-in-Chief and Reviewers,
Please find here attached our answers to the minor revisions.
Sicerely,
The authors.
Author Response File: Author Response.pdf
