Throughput Analysis for Wireless Full-Duplex Multi-Hop Networks with RTS/CTS-Based MAC

Round 1

Reviewer 1 Report

The paper in general is written well. However, the following points should be addressed in the paper.

1. Write-up of the paper need to be revised, e.g.,

• Line 6: Sentence “cannot be applied to performance analysis of wireless” needs grammatical corrections.
• Some acronyms are not defined at first use, e.g. WLAN in line 24.
• Sentence in Line 82-84 needs rephrasing.
• Sentence in Line 174-175 needs rephrasing.

2. Authors should mention in the reply letter that what has been extended from the conference paper.
3. Introductions section should include a paragraph on the organization of the content.
4. Motivation of the paper in the introduction needs some improvement. Presently, Ref [17] and its limitations are pointed out, perhaps more references shall be included and the limitations therein should be pointed out to justify the need of the work.
5. Analysis and simulation results have some degree of mismatch beyond 3.59 value in Fig. 9. What is the reason for that? Also, same is the case for Fig. 11 as well.

 

Author Response

The paper in general is written well. However, the following points should be addressed in the paper.

1.  Write-up of the paper need to be revised, e.g.

   1. Line 6: Sentence "cannot be applied to performance analysis of wireless" needs grammatical corrections.

      • We have rephrased that sentence as 

        `` the conventional model cannot analyze the performance of wireless multi-hop networks with RTS/CTS--based FD MAC.'' 

        As similar to the above, in the revised manuscript, lines 33 and 180 are rephrased. 

   2.  

      Some acronyms are not defined at first use, e.g. WLAN in line 24.

      • We revised as the reviewer's pointed out and rechecked the other acronyms. 

   3. Sentence in Line 82-84 needs rephrasing.

      • In the revised manuscript, we have rephrased the sentence as follows: (Line 95-97)

        "However, in real-world ad-hoc network systems, it is assumed that the network topology or wireless link quality varies frequently due to node mobility, channel fading, and interference.''

   4. Sentence in Line 174-175 needs rephrasing.

      • In the revised manuscript, we have rephrased the sentence in Line 82-84 as follows: 

        (Line 193-194) 

        "the extended analytical model for multi-hop networks with RTS/CTS has not been proposed to date.'' 

2. Authors should mention in the reply letter that what has been extended from the conference paper.

   • The fundamental idea is similar to the conference paper. This paper includes has the more detailed explanations regarding the related works in section 2 and the analytical expressions in section 3 than the conference paper. As mentioned in line 231 on page 8, the analytical expressions presented in this paper can be easily applied to analysis for FD multi-hop networks without RTS/CTS-based FD MAC. This is the technical extended point from the conference paper. Section 4 discusses the network-throughput gain caused by full-duplex communication under the use of exchanging control frames.   

3. Introductions section should include a paragraph on the organization of the content.]

   • In the revised manuscript, we added the paragraph on the organization of the content into the introduction section. 

4. Motivation of the paper in the introduction needs some improvement. Presently, Ref [17] and its limitations are pointed out, perhaps more references shall be included and the limitations therein should be pointed out to justify the need of the work.

   • We added the explanations of two papers, which are related to theoretical analysis of multi-hop networks with RTS/CTS and another approach performance analysis for a multi-hop network with RTS-CTS-based FD MAC, in the introduction section of the revised manuscript. In addition, we mentioned the limitations of those papers from the viewpoint of establishing the analytical model of multi-hop network with RTS- CTS-based FD MAC. 

     Related to the added explanation in the introduction (Line 41-49), we also added the detailed explanation in Section 2 (Line186-189).  

5. Analysis and simulation results have some degree of mismatch beyond 3.59 value in Fig. 9. What is the reason for that? Also, same is the case for Fig. 11 as well.

 

• • There are various factors of such a mismatch. One of the main causes comes from the assumption that the transmission failure probability γ is constant for all of the backoff stages. This means that the transmission failure probability for each backoff stage is assumed as a constant value, which is averaged by the transmission failure probability of each backoff stage. 

    Because of the characteristics of data relay in multi-hop networks, however, transmission failure probability for each backoff stage is different. 

    Caused by this assumption, the quantitative errors, which are the analytical results beyond the simulation ones, tend to appear especially for the longer payload size P. In addition, the fundamental operation in control-frame exchanging in multi-hop networks more affects the quantitative errors when the payload size is longer, as mentioned in lines 351-361 on Page 18. 

    In the case of shorter payload size, on the other hand, the quantitative errors, which are the simulation results beyond the analytical ones, appear. This is also because of the assumption.  

    A node in the network does not fail the RTS frame transmissions repeatedly during shorter NAV durations for smaller P. Therefore, it is stated that the transmission failure probability in the higher backoff stage tends to be an extremely small value. Therefore, it is stated that the gap between the assumption and the behavior of multi-hop networks causes such quantitative error. 

    Even the proposed analytical expression includes some quantitative errors which come from the assumption, the qualitative verification of the proposed model is confirmed from all of the results presented in this paper. We believe qualitative verification is also important and useful from the viewpoint of clarifying complex behavior in networks. 

    In the revised manuscript, we added the above explanation in the last paragraph of Section 4. 

 

 

Author Response File: Author Response.pdf

Reviewer 2 Report

In this paper, authors have proposed the model for throughput analysis for multi-hop networks. The proposed model is capable to handle request to send/clear to send operations. Detailed analysis of the proposed model is presented. The analytical results are validated by the simulated results. Paper is well written. Authors are suggested to include the following corrections:

1. Authors have defined most of the abbreviations, please define the abbreviation ‘MAC’ in the abstract as well.
2. ‘full duplex networks (FD MAC)’ should be corrected as ‘full duplex MAC (FD MAC) networks’’
3. There are some grammatical errors in the paper such as in abstract and page 2 (line 47) ‘which allow us’ should be written as ‘which allows us’ etc.
4. At some places authors have used ‘Figure’ and at some places, authors have used ‘Fig.’ in the text. Please use uniform either ‘Figure’ or Fig.’ as per format.
5. In Fig. 8, please use different colors for different graphs.
6. Why frame existence probability and end to end throughput are constant after a specific value of load? Please explain in the text.
7. The page numbers of Ref. [3] are missing.
8. Please include ‘,’ between volume number and page numbers in Ref. [4], Ref. [5], Ref. [6], Ref.[8] etc.
9. In some references ‘pp. x-y’ is used and in some references ‘x-y’ is used. Please use uniform format as per the format. Page numbers in some references are missing.

Author Response

In this paper, authors have proposed the model for throughput analysis for multi-hop networks. The proposed model is capable to handle request to send/clear to send operations. Detailed analysis of the proposed model is presented. The analytical results are validated by the simulated results. Paper is well written. Authors are suggested to include the following corrections:

1. Authors have defined most of the abbreviations, please define the abbreviation ‘MAC’ in the abstract as well.

   • We revised as reviewer's point out. 

2. 'full duplex networks (FD MAC)' should be corrected as 'full duplex MAC (FD MAC) networks'

   • We revised as reviewer's point out. 

3. There are some grammatical errors in the paper such as in abstract and page 2 (line 47) ‘which allow us’ should be written as ‘which allows us’ etc.

   • We revised as reviewer's point out. And, we have rechecked grammatical errors in the paper as possible. Then we also rechecked through the grammatical check software nameed Grammarly. 

4. At some places authors have used ‘Figure’ and at some places, authors have used ‘Fig.’ in the text. Please use uniform either ‘Figure’ or Fig.’ as per format.

   • Following the MDPI format, we have unified using ‘Figure’ in the revised manuscript.   

5. 5. In Fig. 8, please use different colors for different graphs.

   • As the reviewer's pointed out, we modified Fig. 8 by using different colors.

6. Why frame existence probability and end to end throughput are constant after a specific value of load? Please explain in the text.

   • From Eq. (28), the expression of frame-existence probability includes packet arrival rate λ, which depends on networks offered load O. This means the maximum value of frame-existence probability is 1 even in the network with the higher value of O. Because a node whose frame-existence probability is one has at least one data frame in its buffer, the node becomes a bottleneck in a multi-hop network. 

     As the result, end-to-end throughput in the multi-hop network is limited as the constant value of network offered load, which satisfies the frame-existence probability of the bottleneck node is 1. A similar explanation is shown in [22], which is the first paper that provides the concept of frame-existence probability in a multi-hop network. This is the reason why end-to-end throughput is constant after a specific value. 

7. The page numbers of Ref. [3] are missing.

   • We inserted the page number. 

8. Please include ‘,’ between volume number and page numbers in Ref. [4], Ref. [5], Ref. [6], Ref.[8] etc.

   • We inserted ‘,’ between volume number and page numbers in Ref. [4], Ref. [5], Ref. [6], Ref.[8]. Then, we rechecked all of the references. 

9. In some references ‘pp. x-y’ is used and in some references ‘x-y’ is used. Please use uniform format as per the format. Page numbers in some references are missing.

   • Following the format of MDPI introduced in the web page, we use ‘x-y’ for the case of journal paper, and ‘pp. x-y’ for the case of conference paper. 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Authors have addressed my comments well. The paper can be accepted now.