Hybrid Duplex Medium Access Control Protocol for Tsunami Early Warning Systems in Underwater Networks

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

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Comments for author File: Comments.pdf

Comments on the Quality of English Language

Technical English is adequate, but with some adjustments in fluency, consistency of tenses, and clarity of scientific details, the article can significantly improve its impact and professionalism.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The paper proposes the HDMAC protocol, which seems to be efficient and practical for earthquake and ocean monitoring in Korea. The proposed HDMAC appears to have practical value and good ideas. However, there are a few points that should be considered:

1. Additional Explanation on the Experimental Basis of Physical Layer Parameters
   The author claims that the physical layer parameters for the 1228kHz and 3236kHz frequency bands are based on experimental results. While this seems reasonable, additional explanation of the supporting evidence is necessary since not all readers may be able to review the referenced papers. Providing more details would be helpful.

2. Lack of Supporting Evidence for the Low-Cost Claim
   The author asserts that the HDMAC protocol is low-cost, but there is no evidence provided to support this. It would be beneficial to present the estimated cost of a single buoy, the expected cost of system installation, or the anticipated maintenance costs to substantiate this claim.

3. Packet Optimization
   When a 4000-bit packet size was used, the channel utilization was measured as 0.914 at a distance of 200 meters and 0.64 at a distance of 2000 meters. However, when the packet size was optimized, the channel utilization was slightly lower at 0.912 at 200 meters, and it remained the same at 0.64 at 2000 meters. This could cause confusion for the reader, so it would be helpful to provide further explanation.

4. Lack of Synergy Between FDD and TDD
   The HDMAC protocol does not seem significantly different from operating FDD and TDD networks independently. For example, it would not be an issue to deploy only a TDD network without FDD since their frequency bands and purposes differ. Conversely, the FDD network could function independently without the TDD network. Therefore, calling this a "hybrid" system might be a stretch.

   I suggest exploring ideas where the FDD and TDD networks collaborate based on the situation. For instance, in the event of early signs of a serious earthquake, the TDD network could help transmit earthquake data, improving the efficiency of the earthquake warning transmission. Conversely, if underwater transmission conditions are poor, the FDD network could assist in transmitting environmental data.

I recommend considering these ideas for improvement.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This paper proposed a Hybrid Duplex Medium Access Control protocol for a tsunami warning system, which considered the distinct transmission requirements for each data type by optimizing channel utilization through a group ARQ scheme and packet size adjustment. The manuscript exhibited satisfactory organization and was well written. The simulations also verified the effectiveness of the proposed scheme. However, some issues should also be addressed before its publication.

1.       The abstract should be revised to address the novelty or unique of the work when compared with previous work. Besides, the authors should delete the introduction of the simulation platform but add numerical simulation results for verification.

2.       All the abbreviations should be used after being explained, especially in the abstract, such as FDD, TDD, and ARQ.

3.       In the introduction, the authors should add the contributions of this manuscript.

4.       The clearness of some figures, such as Fig. 2(b), Fig.11, are not satisfactory, which need improvement.

5.       In Table 3, the authors should address the selection of the employed parameters.

6.       For the conclusion “The optimized packet size is 3000 bits for a smaller network and 1600 bits for a larger network, as shown in Figure 9”, the authors should provide more specific explanation.

 

Author Response

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Author Response File: Author Response.pdf