A Radio over Fiber System with Simultaneous Wireless Multi-Mode Operation Based on a Multi-Wavelength Optical Comb and Pulse-Shaped 4QAM-OFDM

Round 1

Reviewer 1 Report

1-The system architecture should be explained in detail as well as the function block diagrams.

2-Please explain the most effective parameters to vary the channel spacing of the generated comb.

3-The introduction could be improved and include more recent publications.  

Author Response

Original Manuscript ID: electronics-513619

Re-submission ID: electronics-557674

Manuscript ID: electronics-589571

Article Title: “A Radio over Fiber System with Simultaneous Wireless Multi-Mode Operation Based on Multi-wavelength Optical Comb and Pulse-Shaped 4QAM-OFDM”

To: Electronics Editor

Re: Response to reviewers

Dear Editor and Reviewers,

Thank you for allowing a revision of our manuscript, with an opportunity to address the reviewers’ comments.

We are uploading (a) our point-by-point response to the comments (below) (response to reviewers), (b) an updated manuscript with green or light blue highlighting indicating changes (WORD main document), and (c) an updated manuscript without green or light blue highlights (PDF main document).

Best regards,

Guang Li, Zhihua Lin, Xuguang Huang, and Jianqing Li

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper studies a radio over fiber transmission system with simultaneous multiple wavelength optical comb and pulse shaping. Authors claim a multi-wavelength optical comb with flat optical wavelengths and tens of GHz spacing is achieved by properly configuring the RF-optics modulation parameters. 

The paper is poorly written and there are many unwarranted claims and confusing statements. For example, it is surprising to know a multi-wavelength optical comb with 13 flat optical wavelengths and a wavelength space of 10 GHz is achieved by using RF-optics modulation and parameter configuration. 

There is no experimental verification which is a major drawback. I would say realizing such a complex system in hardware and achieving the given performance would be next to impossible. 

Author Response

Original Manuscript ID: electronics-513619

Re-submission ID: electronics-557674

Manuscript ID: electronics-589571

Article Title: “A Radio over Fiber System with Simultaneous Wireless Multi-Mode Operation Based on Multi-wavelength Optical Comb and Pulse-Shaped 4QAM-OFDM”

To: Electronics Editor

Re: Response to reviewers

Dear Editor and Reviewers,

Thank you for allowing a revision of our manuscript, with an opportunity to address the reviewers’ comments.

We are uploading (a) our point-by-point response to the comments (below) (response to reviewers), (b) an updated manuscript with green or light blue highlighting indicating changes (WORD main document), and (c) an updated manuscript without green or light blue highlights (PDF main document).

Best regards,

Guang Li, Zhihua Lin, Xuguang Huang, and Jianqing Li

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Thanks for your lengthy explanations and revision of the manuscript. It looks better now. Please do the following changes:

Page2: If RF signals with multiband mode can be directly transformed from an optical comb, which will be an unusual method --> If multiband RF signals can be directly transformed from an optical comb, it will be an unusual method.

Page5: Consequently, it can accomplish the transport of radio signals in a centralized radio network center (i.e., CS) via the architecture of CS + RRUs + MTs. And then, the schematic diagrams of spectra for the key points on the optical and microwave transmission links (i.e., ‘a’, ‘b’, ‘c’, ‘d’, and ‘e’, shown
in Fig. 2 and Fig. 3) are shown in Fig. 4. --->

Consequently, the transport of radio signals in a centralized radio network center (i.e., CS) can be accomplished via the architecture of CS + RRUs + MTs. Using this approach, the schematic diagrams of spectra at the key points on the optical and microwave transmission links (i.e., ‘a’, ‘b’, ‘c’, ‘d’, and ‘e’, as shown in Fig. 2 and Fig. 3) are shown in Fig. 4.

There are many such lengthy, confusing sentences sometimes with grammatical mistakes. Please check all the verb for singularity and plurality agreement. Example, Page 11: From Fig. 14 and Fig. 15, it can be seen that the original constellation of the 4QAM signals is very regular; however, when 4QAM signals are processed by OFDM again, the constellation of the 4QAM-OFDM signals changes a lot and become disorganized.

Please add the following references:

_________‘Radio over Fiber for Wireless Access – From Fundamentals to Advanced Topics’, http://ca.wiley.com/WileyCDA/WileyTitle/productCd-111879706X.html

_______“Analysis of Sub-Carrier Multiplexed Radio over Fiber Link for the Simultaneous Support of WLAN and WCDMA Systems”, Kluwer Wireless Personal Communications Journal, Vol. 33, No. 1, pp. 1-20, April 2005

_______ ‘Adaptive Performance Improvement of OFDM Radio over Fiber Systems’ International Symposium on Signals, Systems and Electronics, (ISSSE '07), Page(s):611 – 614, July 30-Aug, 2, 2007

Author Response

Dear reviewer #2,

I am glad to receive your suggestions. Your constructive suggestions can make our paper improve a lot. Thank you very much for your support for our academic research.

Comment #1: The Page2: If RF signals with multiband mode can be directly transformed from an optical comb, which will be an unusual method --> If multiband RF signals can be directly transformed from an optical comb, it will be an unusual method.

Response #1: OK. It is a good suggestion. Thank you very much. This sentence has been resived as “If multiband RF signals can be directly transformed from an optical comb, it will be an unusual method”.

Comment #2: Page5: Consequently, it can accomplish the transport of radio signals in a centralized radio network center (i.e., CS) via the architecture of CS + RRUs + MTs. And then, the schematic diagrams of spectra for the key points on the optical and microwave transmission links (i.e., ‘a’, ‘b’, ‘c’, ‘d’, and ‘e’, shown in Fig. 2 and Fig. 3) are shown in Fig. 4. ---> Consequently, the transport of radio signals in a centralized radio network center (i.e., CS) can be accomplished via the architecture of CS + RRUs + MTs. Using this approach, the schematic diagrams of spectra at the key points on the optical and microwave transmission links (i.e., ‘a’, ‘b’, ‘c’, ‘d’, and ‘e’, as shown in Fig. 2 and Fig. 3) are shown in Fig. 4.

Response #2: OK. It is a good suggestion. Thank you very much. This sentence has been resived as “Consequently, the transport of radio signals in a centralized radio network center (i.e., CS) can be accomplished via the architecture of CS + RRUs + MTs. Using this approach, the schematic diagrams of spectra at the key points on the optical and microwave transmission links (i.e., ‘a’, ‘b’, ‘c’, ‘d’, and ‘e’, as shown in Fig. 2 and Fig. 3) are shown in Fig. 4”.

Comment #3: Page 11: From Fig. 14 and Fig. 15, it can be seen that the original constellation of the 4QAM signals is very regular; however, when 4QAM signals are processed by OFDM again, the constellation of the 4QAM-OFDM signals changes a lot and become disorganized.

Response #3: It is a good suggestion. Thank you very much. This sentence has been resived as “From Fig. 14 and Fig. 15, it can be seen that the original constellation of the 4QAM signals is very regular. The constellation become disorganized when 4QAM signals are processed by OFDM”.

Comment #3: Please add the following references:

“Radio over Fiber for Wireless Communications: From Fundamentals to Advanced Topics”, http://ca.wiley.com/WileyCDA/WileyTitle/productCd-111879706X.html;

“Analysis of Sub-Carrier Multiplexed Radio over Fiber Link for the Simultaneous Support of WLAN and WCDMA Systems”, Kluwer Wireless Personal Communications Journal, Vol. 33, No. 1, pp. 1-20, April 2005

“Adaptive Performance Improvement of OFDM Radio over Fiber Systems” International Symposium on Signals, Systems and Electronics, (ISSSE '07), Page(s):611 – 614, July 30-Aug, 2, 2007

Response #3: It is a good suggestion. Thank you very much. In order to make this paper better and more complete, these useful references have been added, which can be seen in the INTRODUCTION section and REFERENCES section with green highlights in the revised manuscript.

Author Response File: Author Response.pdf