Joint Constellation and Reflectance Optimization for Tunable Intelligent Reflecting Surface-Aided VLC Systems
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsTitle: Comments on joint Constellation and Reflectance Optimization for Tunable Intelligent Reflecting Surface-Aided VLC systems
In this manuscript, a new electro-tunable intelligent reflecting metasurface is proposed for tunable VLC systems using the intensity modulation and direct detection (IM/DD) scheme to reduce the bit error rate. The manuscript suffers from a lack of novelty. However, the following comments are suggested to improve the quality of the manuscript:
1- The manuscript contains a limited number of sources. Additional papers related to the topic should be included in the manuscript.
2- The comparison provided in Figure 2 is incomplete. The graphs for ξ=0.3, 0.5, and 0.7 should be separated for other figures to improve the comparison. The bit error rate for ξ=0.3 and ξ=0.7 with tunable IRS and mirror-based IRS should also be compared.
3- We shouldn't rely solely on the bit error rate (BER) criterion to evaluate the performance of the proposed system. It's important also to examine other parameters, such as the optical current in the receiver, and compare its improvement to traditional visible light communication systems.
4- In this manuscript, it is important to assess the performance of other modulations such as QAM, and select the best modulation for the proposed system.
5- The results should be extended, compared, and confirmed with other experimental research.
6- To demonstrate an improvement in the paper's quality, it is necessary to showcase the BER improvement across various tetaRK,DMS (the angle of DRk and the unit normal vector of the k-th IRS unit) and identify its optimal value.
7- The results should include the effects of increasing the transmitter power, the distance of the communication channel, and the background light on the performance of the proposed system.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for Authors In this paper, the authors proposed a joint constellation and reflectance optimization algorithm for the tunable IRS-aided VLC system. The paper contains a clear description of the motivation and formulation of the problem. The algorithm proposed has been fully demonstrated with simulation results to evaluate the performance of the optimized constellation and reflectance. Over all, it is a solid work with completeness and the importance and timeliness addressed is good within its area of research.
But, there are a few confusions in the paper that may not help to follow and understand, which are listed as suggestions. This paper is recommended for publication after minor revision based on the improvement below.
1: The angles in line 84-86 are illustrated with the xyz axes. It would be better if they are described by the angles of irradiation and angles of incidence.
2: The reflection matrix R in line 123 is not defined in the manuscript. I believe it is the coherent reflectance vector \bar{r}. Please fix it.
3: Equation（13）is derived by（8）（9）an (11). It would be better if the detailed deducing process is shown in the manuscript.
4: In the whole manusript, the IRS reflected channel are denoted by NLoS channels. However, the diffusely reflected NLoS channels are ignored. I suggest authors replacing the NLoS channels by the IRS reflected channels.
5. This paper mainly studied the passive IRS, which is well known to suffer from the double path fading effect. To address this issue, the researchers have proposed the novel concept of active RIS, which is equipped with amplifers. Pls refer to the following paper for more details: Active RIS versus passive RIS: Which is superior with the same power budget?
6. The introduction lacks some important tutorial papers in this area. To help readers understand the recent advance in this area, the following important paper should be acked:
An overview of signal processing techniques for RIS/IRS-aided wireless systems
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manuscript is revised according to the comments and recommendations. However, the revised version needs some minor revisions as follows:
- The response to the 6th comment can be reflected in the context, at least in the Conclusion section.
- A list of all abbreviations (and symbols) at the end of the manuscript is recommended which can be useful for readers.
- A brief comparison of the presented results and previous works can highlight the novelty of the manuscript (a suggestion).
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsI have no further comments.
Author Response
Thanks for your comments. We sincerely appreciate your time to review our manuscript
