Energy Efficiency of IoT Networks for Environmental Parameters of Bulgarian Cities

Round 1

Reviewer 1 Report

The article presents a study on some aspects of the sensor networks that have been created in Hungary. Some characteristics of the sensor networks of seven cities are presented. References are appropriate for this type of article. Some more reference could have been included as indicated below. English is adequate. The structure of the article is adequate.

Some aspects to improve the proposal.

Lines 80-81. any synonym of measurement?
Line 85. Some reference must be added.
Lines 99-102. I don't quite understand the paragraph, does it mean that most of the articles present simulated scenarios?
TABLE 1. Some technologies are missing in the table, for example: 4G, 5G and Sigfox.
Line 123. Reference about Lorawan and its protocols.
Table 2. More parameters could be added about the sensors in each city: average distance, type of sensors, etc.
Equation 18. The formula is that of the received power, not of the distance as it says in line 248.
Equation 18. Why has the Free Space Propagation Model been used?
Equations 3,4 and 5. A function f() appears but that function f is never defined.
Section 3. All sensors are simulated with the same characteristics, is that true in reality?
Section 4. The results are consistent with the schemes presented, but in FIG 6 for T1 (light blue) it seems that linear growth is lost in the last rounds. Why?
Conclusions. The conclusions are obvious. It could be better explained how this analysis could be used in IoT scenarios (lines 395-398).

Author Response

First of all, we would like to thank the members of the editorial and reviewer boards for their objectivity and accuracy in evaluating the materials presented in the article, for the positive evaluation of the results of the work, and especially for the advice and recommendations for our research. We consider the remarks made regarding technical errors, insufficiently substantiated methods and tools and partial omissions to be justified.

Author Response File: Author Response.docx

Reviewer 2 Report

The paper addresses a topical subject and the results can be claimed by the authors.

The study of current implementations (Introduction and Related Work) is a little superficial. This paper is not included in the papers published so far, nor does it emphasize the novelty that it brings.

A third of the references that are cited in the state of the art section are more than 5-10 years old. Therefore, the study is no longer up to date. Using more recent research works would help placing the paper in the corresponding research field.

I could not find in the documentation the information included in Table 3 (Transmitting power 100 W?). Shenzhen Dragino sells 12 gateways and countless types of nodes. Could you specify more clearly the models under consideration?

A big problem related to the application of formula [1] is that there are certain parameters that are often not known correctly: Pt, Gt, Gr, but also d - distance. The distances calculated in Figure 2 should be validated by measurements for a number of nodes: for example, a node appearing at 2-10 km may be less than 1 km behind a tall building.

The paper presents useful statistical data: the location of the nodes and their distribution to the gateway; maximum energy consumption; average level of energy consumption; energy consumption levels; number received packets.

The paper ends without proposing a solution that optimizes something. I quote "It has been found that the performance of wireless sensor networks can be optimized by applying appropriate routing protocols, which are proposed in the available literature."

Author Response

First of all, we would like to thank the members of the editorial and reviewer boards for their objectivity and accuracy in evaluating the materials presented in the article, for the positive evaluation of the results of the work, and especially for the advice and recommendations for our research. We consider the remarks made regarding technical errors, insufficiently substantiated methods and tools and partial omissions to be justified.

Author Response File: Author Response.docx

Reviewer 3 Report

The paper is quite interesting and presents simulation results for a deployment. However, there are several issues that should be considered in order to improve the paper. The results should be presented in a better way in order to see the contribution.

 

Find attached the following comments:

 

In Section 1, line 104, check the following sentences “ In addition, power management on 802.15.3 is easier than on 802.11e. For ZigBee and Bluetooth. Baker [7] points out that the ZigBee over 802.15.4 protocol has more application capabilities than Bluetooth due to its long battery life, greater usable range, dimensional flexibility, and reliability of the network architecture. “

 

In Section 1, Table 1 should include also a column for main applications for each technology.

 

LoraWAN requires a reference itself. And it should be mentioned within this technology the https://www.thethingsnetwork.org/

 

Please, double check the parameters between line 129 and 143.

 

Please, put references to each section in the last paragraph of section 1 to introduce the paper, where you explain how the paper is structured.

 

In section 2, Figure 1 should be included the scale of 1 km. Also, it should be interesting further details about the location, such as hilly vs flat terrain, weather conditions, position of the gateway, etc.

 

Equation 2 is not clear. Do you include the energy for each process? Thus, you should weight in a duty cycle the % of energy consumed by each process. Using a simple average, all of them are considered the same. Or in case that each Ei includes all of them already weighted, explain properly.

 

Be careful when using Pr both for power received and received packets. Also, in line 302 it is said: of maximum energy consumption (Pr)

 

The detail depicted in Table 3, it deserves also a reference to the product 868MHz (Shenzhen Dragino technology development Co., LTD, PR China.

 

Where PCA component analysis is used? Why? Between lines 290 and 296. Although several results are included, it should require further explanation and the goals. It should be clear and simpler.

 

Figure 2 requires further explanation. What is the meaning of blue points, green lines, black disk, etc. If there is no connection (green line), what does it mean? In the same line, Figure 3 requires further explanation, is it plots maximum energy consumption (Pr)?

 

In line 320, explain this sentence: “Only in T1, due to the presence of a number of nodes near the base station, when transmitting more than 30 rounds, there is an increase in energy consumption.”

 

Figure 5 is confusing. Is it constant? Why? Do you use solar panels? Figure 5. Remaining energy levels for WSN by cities.

 

In general, although “jules” is used for energy, it is better to use other parameters such as watts.

 

Also, to motivate the paper in Section 1, line 70, along with reference [4] it could be interesting to include an example of real time soundscape monitoring scenario such as the one described in "Enabling realtime computation of psycho-acoustic parameters in acoustic sensors using convolutional neural networks," in ieee sensor journal doi: 10.1109/jsen.2020.2995779.

 

English should be reviewed. There are several grammar typos:

Line 44: “and analyzes of the data received”- > and analysis of the data received”

 

Minor issues:

1.- line 34 is broken

2.- abbreviations are defined several times and others are not used. They should defined once and after that always. For instance, wireless sensor networks

3.- after :, ;, , etc it should be used lower letters and capital letters after “.”

Author Response

First of all, we would like to thank the members of the editorial and reviewer boards for their objectivity and accuracy in evaluating the materials presented in the article, for the positive evaluation of the results of the work, and especially for the advice and recommendations for our research. We consider the remarks made regarding technical errors, insufficiently substantiated methods and tools and partial omissions to be justified.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors have made the requested changes satisfactorily.

Author Response

We would like to thank the reviewers and the members of the editorial board for their thoughtful comments and efforts towards improving our paper. In the following, we highlight general concerns of reviewers that were common and our effort to address these concerns. We then address comments specific to each reviewer below.

Author Response File: Author Response.docx

Reviewer 2 Report

I read the review questions and the way the authors responded and improved the content of the paper.

The authors have clarified all the aspects and they have modified the paper accordingly.

Author Response

We would like to thank the reviewers and the members of the editorial board for their thoughtful comments and efforts towards improving our paper. In the following, we highlight general concerns of reviewers that were common and our effort to address these concerns. We then address comments specific to each reviewer below.

Author Response File: Author Response.docx

Reviewer 3 Report

Thanks for your response. The paper has been improved.

However I can still find some minor issues:

1.-references within the text have different formats
2.-first paragraph in the introcution still shows a wrong carry return within low-cost word.

3.- figure  7 (Number received packets of WSN by cities ) it should mention that different plots are overlapped or something wrong is with this figure.

4.- figure 8 (Principal component analysis of WSN), could you include the detail of variables within PC1, PC2 and PC3 after PCA process?

5.- it should mentioned explicitaly "multihop" if it is used, not used, pros/cons since it would be directly related with your proposal.

Author Response

We would like to thank the reviewers and the members of the editorial board for their thoughtful comments and efforts towards improving our paper. In the following, we highlight general concerns of reviewers that were common and our effort to address these concerns. We then address comments specific to each reviewer below.

Author Response File: Author Response.docx