Addressing the Directionality Challenge through RSSI-Based Multilateration Technique, to Localize Nodes in Underwater WSNs by Using Magneto-Inductive Communication

Round 1

Reviewer 1 Report

I am satisfied with the authors' response and consider the manuscript publishable subject to minor language editing.

Author Response

hello reviewer I hope you find this message in good health.

plz, find the attachment as a response to your suggestions.

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Overall rating for the paper is good and results has merit to be publish but few suggestion for the improvements are given as follows:

In the abstract, problem statement "Underwater and underground wireless sensor networks (UWSNs) have a variety of applications in magneto-inductive (MI) communication. To make the magneto-inductive underwater wireless sensor networks (MI-UWSNs) more efficient, recently, various research studies are focusing on the optimization of the physical layer, MAC layer, and routing layer. Despite the directionality issue posed by the physical nature of a magnetic field, the unique qualities of MI communication open up several applications in non-conventional mediums. The directionality issue of MI sensors is a critical challenge that must be taken into account while developing any WSN proto-col or localization algorithm ." is bit long, while the detailed of qualitative and quantitative conclusions or inferences is missing. 

2. Introduction section should be narrated with state of the art literature review for better understanding and justification of the problem statement. Moreover, the contributions, insights and novelty aspect of the proposed study should be listed at the end of the introduction section.

3. Summary of the organization of the paper should be listed in last paragraph of introduction section with more elaborative details

4. Pseudo code of the proposed methodology should be provided with sufficient description for ease in reproduction of the results.

5. More comparative study of the proposed method with last state of the art should be provided to prove the worth of the proposed scheme.

6. Necessary interpretation of all graphical and numerical illustrations in the form of figure and table should be given to decipher the underlying inferences more evidently. 

7. Limitation/advantages/future Scope of the presented study should be given in the conclusion section.

8. References should be given on consistent template and preferably given on the template of the journal.

Author Response

hello reviewer we hope that you find this reply in good health.

plz, find the attachments, where we have shown all the incorporated changes in the original draft as per your suggestion.

Author Response File: Author Response.pdf

Reviewer 3 Report

1.The authors examine the directionality issues in designing localization algorithm for magneto inductive wireless sensor networks (MI-WSNs). The paper topic is significant and prospective.

2.In the paper, a RSSI-based multilateration localization algorithm has been proposed and evaluated. The role of blind areas in the accurate localization of Rx nodes is described.

3.It may be interesting to point out some possible optimization problems/models (including variables, objective function(s), constraints) in the designing the physical layer, MAC layer, and routing layer of  underwater and underground wireless sensor networks (UWSNs).

4.In the paper bibliography of some journal titles are absent. It is necessary to correct the reference list.

5.It is necessary to extend the abstract.

6.It may be useful to add the references on recent survey articles on wireless sensor networks.

7.It may by useful for readers to add a simplified illustrative figure of underwater WSNs.

 

Author Response

hello reviewer I hope you find this message in good health.

plz, find the attachment. As we have incorporated all the suggestions you provide us in your review

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Revised manuscript improve and no further comments

Reviewer 3 Report

1.In the paper the directionality issues in designing localization algorithm for magneto inductive wireless sensor networks (MI-WSNs) are studied.

2.The authors propose and evaluate a RSSI-based multilateration localization algorithm.

3.In the improved paper version the bibliography list is corrected and extended (including recent surveys).

4.The abstract is extended.

5.The improved paper material may be of interest to many readers.

6.Now the paper can be accepted (as is).

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Paper cope with the problem of localization of vessels in an underwater environment by the use of Magneto Inductive communication technology. The authors aimed at presenting the results of their  developments in a case where the vessels work in structured environment including (presumably) transmitting buoys.

 

The paper is not easily readable probably for the level of english that in some places create problems of understanding. Anyway, in my view, there is the need to better explain and describe the meaning of the pictures presented along the article, especially from the point of view of the hypothesis done about the dimensions of the receiving areas and the blind spots (that are apparently areas and not spots).

Basically I found a bit confusing the reference to Underwater communication Networks. Usually, in this case, the localization problem refers to the localization, by a vessel, of another vessel (or many) to avoid collisions, to calculate a coherent navigation, to start appropriate actions. Apparently, in the article, the authors address instead the problem of the self localization of the vessel by means of “anchor nodes” transmitting information. This is certainly a relevant problem itself to cope with, but is less critical for the operation of a number a vessel and is usually well solved with an acoustical approach provided that there exist the possibility to operate in a structured field. Nevertheless the suggestion of using a magneto inducted fields is interesting especially for short range navigation (few meters among vessel to vessel) and I considered this approach potentially exploitable also for networks of underwater Vessels. This point of view should be not disregarded  in a possible future paper or in a review of this one.

Coming to more specifical points it is important to understand what the authors have in mind in the first pictures and specifically in pictures a,b and c of figure 4. The angles that the author reports with some precision seems just be referred to the area of self-localisation that the author have in mind. In the real case this area will depend from the need of operation and will be affected by the streght of the magnetic fields, by the sensitivity of the magnetic sensors, by the noise induced by the terrestrial magnetic field (that is not static as is generally supposed but  featured by fast or slow variations most of the times dependant by the specific place. So the two represented cases of an area inscribed into an arbitrary iso-intensity magnetic flux are not worthy to give specific angular data, but just to represent a concept. Additionally a wouldn’t talk of “spots” because we are just managing areas that can be also wide and perhaps connected.

Another point that I was unable to understand is the difference between the Configuration 1, when the tridimensional induction is allowed and the Configuration 2, when it isn’t. Ok, there is an energy advantage and a communication rate disadvantage, but the difference between the switching times with respect to the dynamics of real vessels is so huge that you can safely consider that the MEAN value of RSSI in the two cases is identical.  If this is not the case then I have to consider that this part has been badly explained and I strongly suggest to review all the strategy of description of the proposed technique.

Least but not last I would suggest that the localization algorithm should be described in a more detailed way that I found in the paper, being this algorithm at the very end the core itself of the suggested technology.  Other clarifications could be requested about the meaning of “estimation accuracy”, defined at page 9 as just a ratio among to angles relevant to the areas where the RSSI is considered adequate or not adequate.

 

In conclusion I would not recommend this paper for publication as it is. A deep revision should be carried out taking into account the clarity of language, a clear explanation of the figures and the consideration at least of the themes I indicate above in my notes. The paper could be represent after the amendments done.  Just as a suggestion please take in mind that perhaps the stronger need for navigation of groups of vessels in free areas (unstructured)  is the identification of the relative position. A short range magnetic induced field (to avoid the superimposition of effects coming from several vessels) could be an interesting and novel approach.

Author Response

hello sir 

i hope you find this reply in good health.

i have made the required changes as suggested by your kind comments.

i have also tried to better the English structure of the paper. 

to see changes according to your suggestion "please see the attachment"

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper addresses the directionality issue regarding underwater wireless sensor networks (UWSNs) that use magneto-inductive (MI) communication.  

The paper does include novel and interesting material which it presents in an adequate and scientifically sound manner. I have no remarks regarding the paper’s content.

However, the text needs extensive editing with regard to the use of English. Some specific comments can be seen below:

• In the title, the word “Exploiting” may not be proper. Based on the paper’s content, I would suggest the word “Addressing”.
• Lines 24-27 (in the abstract) need rephrasing – it is not clear (at least to me) what the sentence means.
• The justification of using Table 2 instead of graphs should be rephrased
• In several occasions (e.g. in section 5 “Conclusion”) there are periods where commas should be used.   

I consider the paper publishable subject to language editing.

Author Response

Hello sir 

i hope you find this message in good health.

i have made the suggested changes in my paper.

i have tried my level best to better the English structure of the whole paper.

to find the revised version of the sections you suggested "plz see attachment" 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Dear authors,

 

I received from the editor the review you have done of your paper and I read it.

I was glad to see that some of my suggestions have been implemented in the new version, but I am very sorry to say that there is still some work to be done.  May be quite a lot.

There are two kind of main problems I noticed: a still persistant problem of english and problem relevant to the scientific discussion.

About the english I really STRONGLY recommend to get in touch with a skilled person and rewrite with him the text of the paper. I had not enough time to review all the paper under this point of view, but will report here just one page addressing only the major problems (I mean, there are a number of style issues, but these are problems that make the text difficult to read and understand). Let me show:

 

ROW 62: “as the reasons are described ….” use of “as” in this context is quite questionable, probably something among since and though. A most simple way to avoid this is to break the sentence in two: something like “Due to unique physical nature of MI Communication, ToA, TDoA, and AoA cannot be used for nodes localization in MI-UWSNs. The reasons of that are shown (better than described) in Table 1”. It’s very easy, plain and without efforts required to the reader. English prefers short sentences.

ROW 63 to 65: “Thus the only range based algorithm’s option, that can be utilized to localize sensor Rx nodes in MI-UWSNs is RSSI based, where the anchor Tx nodes estimate the range of  sensor Rx node, based on the strength of receiving signal”.

Its quite difficult to read and I am not sure it is formally correct. Its enough to change the order of sentences like so (just an example, other options could be adequate):

“Thus an RSSI based algorithm is the only option that can be utilized to localize sensor Rx nodes in MI-UWSNs with anchor Tx nodes estimating the range on the basis of the strenght of received signal”.

It is shorter and much more linear. I really puzzled myself to understand the original sentence.

ROW 75: the subject of the verb “lead” is missing. Should be something like “i twill lead”. Okay, I understood quite well the sense, but this is not the point.

ROW 99: This was really a challenge to me. I wasn’t able to guess the meaning of the sentence for a lot of time. The crucial point is the use of the which as adjective.

“The magnetic field lines shown in Figure. 2 are quasi-static, which operates differently from a far-field magnetic radiation, which is used to perform the task of localizing a 100 sensor Rx nodes in a MI-UWSNs”

I suppose that the meaning should be something like:

“The magnetic field lines are shown in Figure. 2. The field is quasi-static and therefore it behaves differently by a radiative magnetic far-field like the ones usually exploited to perform the task of localization of RX node sensors in MI-UWSNs”

You can note that, apart the more linear expressions, there are a number of other errors in your sentence. This is not a trivial point.

ROW 112: Perhaps you would like to use “With” and not “Which”

ROW 114: directivity/orientation are not a phenomena.

                   “in which …” .

Please no. Break the sentence and start again:

               … more clearly depicted (?) in fig.3.  In this picture four different nodes …

ROW 128: “coils are low cost yet simple do it yourself” we need commas!

                   “coils are low cost, yet simple, do it yourself…”

ROW 130: “TD coils further offer two possible configurations, where each configuration has its own trade off in range vs power consumption”

Where is wrong.

“TD coils further offer two possible configurations, each configuration having its own trade off in range vs power consumption”

ROW 133: “the three coils are coupled to an independent current source shown in Figure. 4(a), by which we are basically allowing”

“By which… ” is wrong. A possible suggestion is:

the three coils are coupled to an independent current source shown in Figure. 4(a). In this picture we assume that each coil independently transmit three distinct (?) signals

 

ROW 135: “This configuration is basically providing us a larger coverage area” well,  ok, but is quite strange. Better

“This configuration provides a larger coverage area”

 And so on along all the text…  I can mention ROW 141, ROW 146 (quite serious) and so on.

I can ensure that when you are reading a scientific paper, so many flaws make the understanding quite a challenge.

Nevertheless there are several others point to discuss:

1. Clarify why configuration 2 cannot be returned to 1 using the superimposition of the 3 coils in time sharing. I have already mentioned this point in my previous note, but without any answer. The effects of the three coils are linearly summable, so why not to switch up in turn all the three coils summing up the potentials obtained on the RX sensor? Should be equivalent to the simultaneous excitation of the three coils.
2. Explain in detail the TX-RX nodes networking operation. It is now clear that TX are fixed whereas the RX sensors are movable. TX are presumably buoys devoted to transmission and allowing the auto localization of RX nodes. It seems that RX cannot transmit to TX… or they can? In a network they should be able to do. Otherwise how can, the collected data, be transmitted back to the coordination center (if any). I supposed that RX are mobile just because otherwise there is no reason to guess their position. Positions should be noted… or not? Everything appears not clear enough.
3. The Figure 5 represent the Max Flux density, but what is the difference B_c2o1 and B_c202? Is B_c2 the field induced by Coil 2? But in configuration 1 it is claimed that all the three coils are simultaneously active. So what?
4. The Figure 6, representing Configuration 2 is still more mysterious. I suppose (there is again no explanation in any place) that B₁ is the field generated by coil 1, B2 the one of coil 2,  but what is B_c3? Why B1 and B2 apparently reach an intensity of 3e^-7 as max flux whereas in Config 1, with all three coils active, the magnetic field do not exceed 1.5e^-7?
5. Other pictures should be also better explained and discussed.
6. I noted that my previous suggestion to consider the most diffused UW-nets composed by all mobile vessels as been neglected. This is not a problem at all for the evaluation of this paper. Just a suggestion for future developments. You could consider to tackle with it in future papers.

 

Anyway, resuming my analisys. I cannot recommend your paper for publication as it is. It requires a careful and massive review of the language, a review of the pictures clarifying all the variables and expressions you used in them and perhaps some review of some concepts relevant to the networking and to the engineering.

I confirm anyway that the basic idea is valid and good so that I would encourage you to carry out the requested job and to represent your work later.

Dear authors,

 

I received from the editor the review you have done of your paper and I read it.

I was glad to see that some of my suggestions have been implemented in the new version, but I am very sorry to say that there is still some work to be done.  May be quite a lot.

There are two kind of main problems I noticed: a still persistant problem of english and problem relevant to the scientific discussion.

About the english I really STRONGLY recommend to get in touch with a skilled person and rewrite with him the text of the paper. I had not enough time to review all the paper under this point of view, but will report here just one page addressing only the major problems (I mean, there are a number of style issues, but these are problems that make the text difficult to read and understand). Let me show:

 

ROW 62: “as the reasons are described ….” use of “as” in this context is quite questionable, probably something among since and though. A most simple way to avoid this is to break the sentence in two: something like “Due to unique physical nature of MI Communication, ToA, TDoA, and AoA cannot be used for nodes localization in MI-UWSNs. The reasons of that are shown (better than described) in Table 1”. It’s very easy, plain and without efforts required to the reader. English prefers short sentences.

ROW 63 to 65: “Thus the only range based algorithm’s option, that can be utilized to localize sensor Rx nodes in MI-UWSNs is RSSI based, where the anchor Tx nodes estimate the range of  sensor Rx node, based on the strength of receiving signal”.

Its quite difficult to read and I am not sure it is formally correct. Its enough to change the order of sentences like so (just an example, other options could be adequate):

“Thus an RSSI based algorithm is the only option that can be utilized to localize sensor Rx nodes in MI-UWSNs with anchor Tx nodes estimating the range on the basis of the strenght of received signal”.

It is shorter and much more linear. I really puzzled myself to understand the original sentence.

ROW 75: the subject of the verb “lead” is missing. Should be something like “i twill lead”. Okay, I understood quite well the sense, but this is not the point.

ROW 99: This was really a challenge to me. I wasn’t able to guess the meaning of the sentence for a lot of time. The crucial point is the use of the which as adjective.

“The magnetic field lines shown in Figure. 2 are quasi-static, which operates differently from a far-field magnetic radiation, which is used to perform the task of localizing a 100 sensor Rx nodes in a MI-UWSNs”

I suppose that the meaning should be something like:

“The magnetic field lines are shown in Figure. 2. The field is quasi-static and therefore it behaves differently by a radiative magnetic far-field like the ones usually exploited to perform the task of localization of RX node sensors in MI-UWSNs”

You can note that, apart the more linear expressions, there are a number of other errors in your sentence. This is not a trivial point.

ROW 112: Perhaps you would like to use “With” and not “Which”

ROW 114: directivity/orientation are not a phenomena.

                   “in which …” .

Please no. Break the sentence and start again:

               … more clearly depicted (?) in fig.3.  In this picture four different nodes …

ROW 128: “coils are low cost yet simple do it yourself” we need commas!

                   “coils are low cost, yet simple, do it yourself…”

ROW 130: “TD coils further offer two possible configurations, where each configuration has its own trade off in range vs power consumption”

Where is wrong.

“TD coils further offer two possible configurations, each configuration having its own trade off in range vs power consumption”

ROW 133: “the three coils are coupled to an independent current source shown in Figure. 4(a), by which we are basically allowing”

“By which… ” is wrong. A possible suggestion is:

the three coils are coupled to an independent current source shown in Figure. 4(a). In this picture we assume that each coil independently transmit three distinct (?) signals

 

ROW 135: “This configuration is basically providing us a larger coverage area” well,  ok, but is quite strange. Better

“This configuration provides a larger coverage area”

 And so on along all the text…  I can mention ROW 141, ROW 146 (quite serious) and so on.

I can ensure that when you are reading a scientific paper, so many flaws make the understanding quite a challenge.

Nevertheless there are several others point to discuss:

1. Clarify why configuration 2 cannot be returned to 1 using the superimposition of the 3 coils in time sharing. I have already mentioned this point in my previous note, but without any answer. The effects of the three coils are linearly summable, so why not to switch up in turn all the three coils summing up the potentials obtained on the RX sensor? Should be equivalent to the simultaneous excitation of the three coils.
2. Explain in detail the TX-RX nodes networking operation. It is now clear that TX are fixed whereas the RX sensors are movable. TX are presumably buoys devoted to transmission and allowing the auto localization of RX nodes. It seems that RX cannot transmit to TX… or they can? In a network they should be able to do. Otherwise how can, the collected data, be transmitted back to the coordination center (if any). I supposed that RX are mobile just because otherwise there is no reason to guess their position. Positions should be noted… or not? Everything appears not clear enough.
3. The Figure 5 represent the Max Flux density, but what is the difference B_c2o1 and B_c202? Is B_c2 the field induced by Coil 2? But in configuration 1 it is claimed that all the three coils are simultaneously active. So what?
4. The Figure 6, representing Configuration 2 is still more mysterious. I suppose (there is again no explanation in any place) that B₁ is the field generated by coil 1, B2 the one of coil 2,  but what is B_c3? Why B1 and B2 apparently reach an intensity of 3e^-7 as max flux whereas in Config 1, with all three coils active, the magnetic field do not exceed 1.5e^-7?
5. Other pictures should be also better explained and discussed.
6. I noted that my previous suggestion to consider the most diffused UW-nets composed by all mobile vessels as been neglected. This is not a problem at all for the evaluation of this paper. Just a suggestion for future developments. You could consider to tackle with it in future papers.

 

Anyway, resuming my analisys. I cannot recommend your paper for publication as it is. It requires a careful and massive review of the language, a review of the pictures clarifying all the variables and expressions you used in them and perhaps some review of some concepts relevant to the networking and to the engineering.

I confirm anyway that the basic idea is valid and good so that I would encourage you to carry out the requested job and to represent your work later. Perhaps it could be a good idea to take some time to re-think the paper from scratch (this is often a precious tool), to ask support to people with a good english knowledge and  (if you want) to take into account also some suggestion that I gave in my previous review.