Energy Efficient Routing in Wireless Sensor Networks: A Comprehensive Survey

Round 1

Reviewer 1 Report

This paper presents a comprehensive survey on energy efficient routing protocols for wireless sensor networks.  

My suggestions for this paper are as follows:

1. The authors should add a summary section to summarize the whole paper and present future research directions. The authors only summarize the whole paper in the conclusion section, I think it is not enough for this survey, and the authors should rewrite this part as it is not good enough and lacks deep considerations.
2. The paper should include all the published papers related to the routing surveys, and tell what is the difference between this paper and other survey or review research.
3. Another related question is that the authors should tell what the main contribution of this paper, what is the motivation for this paper? It is important to height the contributions of this research especially when there has been a lot of related survey and review papers.
4. As I have known that there are numerous survey and review papers related to wireless sensor network routing, but I cannot find them in this paper. For example, “Recent Advances in Energy-Efficient Routing Protocols for Wireless Sensor Networks: A Review,2016”,” Survey on Wireless Sensor Network Applications and Energy Efficient Routing Protocols, 2018”, “Energy efficient routing in Wireless Sensor Networks: A survey, 2016”, to name a few. In my opinion, the authors should find all the related work, and included them in the Introduction section.
5. I also suggest to include energy efficient routing related to underwater sensor networks as they have been developed rapidly recently.
6. I suggest the authors add new protocols related to energy efficient routing protocols. For example, I cannot find this paper “Energy-Efficient Algorithm for Reliable Routing of Wireless Sensor Networks, IEEE Transactions on Industrial Electronics (Volume: 66 , Issue: 7 , July 2019 )), it is better to include more new related research papers in this survey.
7. Another suggestion is that it is better to provide new visions and suggestions for the future research, for example, as AI-based technologies have developed rapidly, how these new methods, such as reinforcement learning and other machine learning techniques, have been applied to wireless routing protocols in order to fulfil energy efficient routing as data-driven AIOT networks?
8. In each subsection, the paper first presents related papers separately, and then only compared them in a Table, it is better to add a paragraph to each table, and present some compared and summarized descriptions.

Author Response

First of all, the authors wish to express their gratitude to the reviewer because the recommendations sent to them helped them to improve the quality of this article.

Reviewer 1

This paper presents a comprehensive survey on energy efficient routing protocols for wireless sensor networks.  

My suggestions for this paper are as follows:

Comment 1:

The authors should add a summary section to summarize the whole paper and present future research directions. The authors only summarize the whole paper in the conclusion section, I think it is not enough for this survey, and the authors should rewrite this part as it is not good enough and lacks deep considerations.

Respond to Comment 1:

Following the beneficial suggestion of the reviewer, Section 7 has been added, as an individual part of the article, in order to highlight both current and future research issues. 

Comment 2:

The paper should include all the published papers related to the routing surveys, and tell what is the difference between this paper and other survey or review research.

Respond to Comment 2:

The research work presented in this article enriches previous surveys of this kind, because it not only studies the greatest, as far as the authors know, number of both classic and brand new energy efficient routing protocols but also proposes new taxonomy subcategories and considers more performance criteria for the comparative study of the protocols studied. This enhancement provided is illuminated in lines 104-107.

Comment 3:

Another related question is that the authors should tell what the main contribution of this paper, what is the motivation for this paper? It is important to height the contributions of this research especially when there has been a lot of related survey and review papers.

Respond to Comment 3:

In lines 101-104 the aims of this research work were clarified, while, as mentioned in the respond to comment 2, the contribution of this work was highlighted in the subsequent sentence.

Comment 4:

As I have known that there are numerous survey and review papers related to wireless sensor network routing, but I cannot find them in this paper. For example, “Recent Advances in Energy-Efficient Routing Protocols for Wireless Sensor Networks: A Review,2016”,” Survey on Wireless Sensor Network Applications and Energy Efficient Routing Protocols, 2018”, “Energy efficient routing in Wireless Sensor Networks: A survey, 2016”, to name a few. In my opinion, the authors should find all the related work, and included them in the Introduction section.

Respond to Comment 4:

It is true that there are numerous survey and review papers related to energy efficient routing. The authors referred to the most cited and well-known and of them in the initial version of this paper. Yet, in Section 1 of the revised manuscript five additional research works of this kind were referred, the ones suggested by the reviewer included. 

Comment 5:

I also suggest to include energy efficient routing related to underwater sensor networks as they have been developed rapidly recently.

Respond to Comment 5:

The reviewer is wright. Indeed, Under Water Sensor Networks (UWSNs) are one the most emerging scientific domains. In Section 7, the authors refer to research challenges that are associated with routing in UWSNs. Please refer to lines 1998-2003.

Comment 6:

I suggest the authors add new protocols related to energy efficient routing protocols. For example, I cannot find this paper “Energy-Efficient Algorithm for Reliable Routing of Wireless Sensor Networks, IEEE Transactions on Industrial Electronics (Volume: 66 , Issue: 7 , July 2019 )), it is better to include more new related research papers in this survey.

Respond to Comment 6:

It is true that dozens of novel routing protocols for energy efficient routing in WSNs are proposed every single month thanks to the high scientific soundness of this domain. The suggested by the reviewer protocol is one protocol of this kind. The authors of this review paper, found it to be a really promising protocol and for this reason they incorporated it in this survey (lines 1714-1722 and Table.13).

Comment 7:

Another suggestion is that it is better to provide new visions and suggestions for the future research, for example, as AI-based technologies have developed rapidly, how these new methods, such as reinforcement learning and other machine learning techniques, have been applied to wireless routing protocols in order to fulfil energy efficient routing as data-driven AIOT networks?

Respond to Comment 7:

Artificial Intelligence methods provide beneficial support to WSNs. This has been discussed in Section 7. Please refer to lines 1979-1985.

Comment 8:

In each subsection, the paper first presents related papers separately, and then only compared them in a Table, it is better to add a paragraph to each table, and present some compared and summarized descriptions.

Respond to Comment 8:

Although the authors tried to follow this suggestion of the reviewer, they did not succeed to implement it in a fruitful way. The addition of paragraphs into the tables resulted to inconsistent and unproductive presentation and this is why, the comparison tables were kept in the typical format that most surveys use.

Reviewer 2 Report

In this paper, the authors provide a survey on both classic and modern protocols, which have been proposed for the achievement of energy-efficient routing in WSNs.

According to the main structural or operational feature, the protocols presented in this paper were classified into four main categories which namely are:  Communication Model, Networks Structure, Topology, and Reliable Routing.

On the whole, this paper shows a comprehensive survey on energy-efficient routing protocols and advances forward-looking thoughts and proposals. However, there are several questions in this paper which may be noticed.

1.  The authors should pay attention to the length of the paper. Currently, it is too long for readers to read. 

2. The authors should pay attention to the case of the first letter of the word. For example, line 152, the problem of inconsistent uppercase and lowercase letters happens in the algorithm name.

3: The authors should pay attention to punctuation in the paper. For example, line 166 “Instead of using the minimum energy path it uses multiple routes with a certain probability to maximize network lifetime. ”, a comma is missed between the word “it” and the word “path”. 

4: The interpretation of the formula is not very clear, we suggest that the authors could give a detailed description of parameters among formula.

Author Response

First of all, the authors wish to express their gratitude to the reviewer because the recommendations sent to them helped them to improve the quality of this article.

Reviewer 2

In this paper, the authors provide a survey on both classic and modern protocols, which have been proposed for the achievement of energy-efficient routing in WSNs.

According to the main structural or operational feature, the protocols presented in this paper were classified into four main categories which namely are:  Communication Model, Networks Structure, Topology, and Reliable Routing.

On the whole, this paper shows a comprehensive survey on energy-efficient routing protocols and advances forward-looking thoughts and proposals. However, there are several questions in this paper which may be noticed.

Comment 1:

The authors should pay attention to the length of the paper. Currently, it is too long for readers to read.

Respond to Comment 1:

The comment made by the reviewer is absolutely true. Actually, the development of this paper was based on a thorough investigation of the state of the art in the domain of energy efficient routing in WSNs. Yet, this domain refers to an ever growing range of protocols of this kind. This is the reason why, the volume of the related information provided in this paper was indeed inevitably big.

Comment 2:

The authors should pay attention to the case of the first letter of the word. For example, line 152, the problem of inconsistent uppercase and lowercase letters happens in the algorithm name.

Respond to Comment 2:

A general rule adopted in the context of this paper, was to use uppercase letters to highlight the letters that constitute the acronyms used by the inventors of some of the protocols presented. However, in line 152 there was indeed a mistake, which was corrected.  The authors thank the reviewer for this.

Comment 3:

3: The authors should pay attention to punctuation in the paper. For example, line 166 “Instead of using the minimum energy path it uses multiple routes with a certain probability to maximize network lifetime. ”, a comma is missed between the word “it” and the word “path”. 

Respond to Comment 3:

The mistake denoted by the reviewer was corrected. Also, an additional proofreading on the whole context of the article was performed.

Comment 4:

The interpretation of the formula is not very clear, we suggest that the authors could give a detailed description of parameters among formula.

Respond to Comment 4:

All formulas used were checked and, wherever needed, more analytical descriptions were given.  Please, refer to lines 438-442, and 986-996.

Reviewer 3 Report

First, thank you for the opportunity to review for this journal. Second, the research design was appropriate for the aim of the research and the results are congruent. However, if I may suggest, the authors should (i) proofread and (ii) add the term ‘further research’ at the end of the term “Conclusions.” This is appropriate given that the conclusion includes areas of research, as suggested by the authors. 

I do not see any major flaws of this article. However, authors should be encouraged to revise their literature review section. There has been much written on this topic that is not discussed. This will only serve to improve the outlook of the research and the journal as well.

Author Response

First of all, the authors wish to express their gratitude to the reviewer because the recommendations sent to them helped them to improve the quality of this article.

Reviewer 3

First, thank you for the opportunity to review for this journal. Second, the research design was appropriate for the aim of the research and the results are congruent. However, if I may suggest, the authors should (i) proofread and (ii) add the term ‘further research’ at the end of the term “Conclusions.” This is appropriate given that the conclusion includes areas of research, as suggested by the authors. 

Comment 1:

I do not see any major flaws of this article. However, authors should be encouraged to revise their literature review section. There has been much written on this topic that is not discussed. This will only serve to improve the outlook of the research and the journal as well.

Respond to Comment 1:

The revised version of the manuscript was enhanced in terms of the literature review as well as the discussion, the future suggestions, and the conclusions. Please refer to Section 7 and the Reference List.