Performance Analysis of Power Allocation and User-Pairing Techniques for MIMO-NOMA in VLC Systems

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper analyzed the NOMA-MIMO-VLC systems with DCO-OFDM, where different Power Allocation schemes and  User-pairing Algorithms are studied. The main concerns are below.

 1.  As illustrated in Sec.3.1, three power allocation schemes are given., i.e.,  FPA, GRPA, and NGDPA. The complexity analysis is suggested to be added.

2. ZF MIMO receiver is utilized. Why the authors do not use MMSE or ML recevier?

3. In numerical results, the circumstances of 2 users, 5 users and 6 users are considered. The reviewer suggests to discuss a more general situation.

4. This paper chooses the "achievable rate" to be the key factor. How do the authors calculate the "achievable rate"? Is it the channel capacity? The equations should be added.

5.The manuscript is well-written and well-structured. However, there are a revision that need to be addressed to further improve the clarity and overall quality of the manuscript. It would be useful for the reader if the authors cited research articles in the introduction.

[1]Y. Li, T. Geng, S. Gao,On the signal combinations for a uniquely decodable coded MIMO-FSO communication system,Optics & Laser Technology,Volume 172,2024, 110533, doi: 10.1016/j.optlastec.2023.110533.

[2]Y. -H. Jian et al., "Optical Beam Steerable Orthogonal Frequency Division Multiplexing (OFDM) Non-Orthogonal Multiple Access (NOMA) Visible Light Communication Using Spatial-Light Modulator Based Reconfigurable Intelligent Surface," in IEEE Photonics Journal, vol. 15, no. 4, pp. 1-8, Aug. 2023, Art no. 7303408, doi: 10.1109/JPHOT.2023.3294834.

 Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

I thank the authors for their efforts and I hope they find my comments helpful and consider them for their future work. I find the following major flaws in the work:

1- The authors did not clearly show novelty in their work

2- I find that the work is in general, simulations of already found results, especially there is an already published conference related to the work

3- The authors did not introduce any kind of optimization assumption, or made comparison with other systems, while noticing that they made a comparison of NOMA performance with OFDMA, which is an already proven result. 

4- minor comment: I find the simulation figures are too many. the authors should chose the most important figures that prove their concept with merging some results in the same figures to give a better comparison.

Comments on the Quality of English Language

The english is very good

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Review of manuscript Photonics 2832833

Performance analysis of power allocation and user-pairing techniques for MIMO-NOMA in VLC systems

By Hesham S. Ibrahim, Mohamed Abaza, Ali Mansur and Ayman Alfalou.

The authors investigated the performance of multiple-input multiple-They used output (MIMO) communication systems used in the indoor visible light communication (VLC). They applied the specific system and channel models for their theoretical investigation and carried the numerical simulations. They developed two novel algorithms for these numerical simulations. The novel results obtained in the proposed manuscript have been compared with the existing results for VLC systems without the allocation techniques for the users grouping. The authors have shown that the proposed power allocation techniques improve the VLC system performance.

 The proposed paper is well organized and clearly written. The paper can be interesting for the researchers and engineers occupied in the field of optical communications.

The manuscript can be accepted for publication in the present form.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

 English Language of the paper is satisfactory.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The revised paper looks fine to me. I recommend that the paper can be accepted.

Reviewer 2 Report

Comments and Suggestions for Authors

no comment

Comments on the Quality of English Language

good