A Wavelength-Dependent Visible Light Communication Channel Model for Underground Environments and Its Performance Using a Color-Shift Keying Modulation Scheme

Round 1

Reviewer 1 Report

In this paper, the authors propose a single-input single-output (SISO) wavelength-dependent UM-VLC channel model, considering the wavelength dependence of the light source, reflections, light scattering, and the attenuation due to dust and the photodetector. The paper is well organized and the work is comprehensively discussed in this paper. However, the reviewer has some queries.

1. In Eq. (1), the Gaussian noise is used. Currently, many noise distributions are studied. However, non-Gaussian noise like Middleton noise model [C1] and alpha distribution [C2], Gaussian mixture models [C3] are further modeled. The reviewer wanders to know whether the authors’ method can work well with these non-Gaussian noise models. The authors must discuss this issue in their paper. This is helpful for readers working in this field.

[C1]Zhang，et al．Parameter estimation of underwater impulsive noise with the Class B model．IET Radar, Sonar & Navigation，2020，Doi: 10.1049/iet-rsn.2019.0477．

[C2]Mahmood, et al, “Modeling Colored Impulsive Noise by Markov Chains and Alpha-Stable Processes,” in OCEANS 2015 MTS/IEEE, (Genoa, Italy), Doi: 10.1109/OCEANS-Genova.2015.7271550.

[C3]He, et al. Image Denoising Using Asymmetric Gaussian Mixture Models. 2018 International Symposium in Sensing and Instrumentation in IoT Era (ISSI). Doi: 10.1109/ISSI.2018.8538279 

2. In Eq. (97), the channel impulse response is modeled. The reviewer wanders to know whether the multi paths should be considered. 

3. The real data is suggested to test the authors’ method.

Author Response

Thank you for your comments, the answer sheet is sent in the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The article has a scientific level and but its structure is not appropriately chosen. With regard to the professional content, this article fully fits into the concept of the given journal. 

The structure of the paper should be significantly reworked. I believe that these my comments will help the authors to improve their article

The structure of the paper should be:

https://www.mdpi.com/journal/electronics/instructions#preparation

Article structure

Research Manuscript Sections

Introduction: The introduction should briefly place the study in a broad context and highlight why it is important. It should define the purpose of the work and its significance, including specific hypotheses being tested. The current state of the research field should be reviewed carefully and key publications cited. Please highlight controversial and diverging hypotheses when necessary. Finally, briefly mention the main aim of the work and highlight the main conclusions. Keep the introduction comprehensible to scientists working outside the topic of the paper.

Materials and Methods: They should be described with sufficient detail to allow others to replicate and build on published results. New methods and protocols should be described in detail while well-established methods can be briefly described and appropriately cited. Give the name and version of any software used and make clear whether computer code used is available. Include any pre-registration codes.

Results: Provide a concise and precise description of the experimental results, their interpretation as well as the experimental conclusions that can be drawn.

Discussion: Authors should discuss the results and how they can be interpreted in perspective of previous studies and of the working hypotheses. The findings and their implications should be discussed in the broadest context possible and limitations of the work highlighted. Future research directions may also be mentioned. This section may be combined with Results.

Conclusions: This section is not mandatory but can be added to the manuscript if the discussion is unusually long or complex.

Patents: This section is not mandatory but may be added if there are patents resulting from the work reported in this manuscript.

Author Response

Thank you for your comments, the answer sheet is sent in the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors did not well addressed the reviewers' comments. For example, the Gaussian noise is usually modeled. Up till now, current communication systems should consider the extension of methods to non-Gaussian models. However, the authors did not present some experiments to verify this. Besides, the multi paths often affect the communication systems. However, the authors just use a sentence to explain this. In general, the authors cannot well respond to the reviewers' comments. At this point, the authors should further enhance their improvements. 

Author Response

Thank you for your valuable comments. In the attached file you will find the answer sheet.

Author Response File: Author Response.pdf

Reviewer 2 Report

Accept in present form

Author Response

Thank you for your valuable comments. In the attached file you will find the answer sheet.

Author Response File: Author Response.pdf

Round 3

Reviewer 1 Report

This paper is suggested to be accepted.