A 5.9 GHz Channel Characterization at Railroad Crossings for Train-to-Infrastructure (T2I) Communications

Round 1

Reviewer 1 Report

The manuscript addresses channel measurements at the 5.86–5.91 GHz ITS band at a group of railroad crossings. The authors extracted the channel parameters and evaluate propagation channel  characteristics using  3 readings at each crossing. The work is interesting and timely, the manuscript is well-written. I have the following minor comments:

1- The authors do not refer to the corresponding figures in their explanations in Section 5 related to the channel parameters.

2- Is 3 readings enough to extract average values of the parameters?

3- I suggest adding another experiment, if possible, to compare the BER/achievable rate of the actual readings compared to the extracted average values of the parameters. 

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

5.9GHz Channel Characterization at Railroad Crossings for Train-to-Infrastructure (T2I) Communications

Few facts about this manuscript are given below:

1. Research contributions in the introduction section are not highlighted clearly.

2. Section 2 literature review section, should have a table for comparing the previous related work with the proposed research.

3. Mathematical equations number 1 to 12 need brief illustrations for better clarity to the readers.

4. More explanation is needed in the Ricean K-factor and Doppler Spread section.

5. Please add limitations and future research directions.

6. Detailed flow chart is needed to reflect the flow of research.

Please find the specific comments as per the following:

1. What is the main question addressed by the research? The main research contribution of this manuscript is channel measurements at 5.9 GHz and data analyses at a typical railroad track in the United States, particularly evaluating channels at rail road track.

2. Do you consider the topic original or relevant in the field? Does it address a specific gap in the field? The topic is quite interesting but sufficient details are missing particularly in the result section and the methodology section. Introduction section is also very short it should highlight key points.

3. What does it add to the subject area compared with other published material? Published articles [15] evaluated the T2I channel in the THz band and [16] evaluated in the 2.6 GHz band. This manuscript shows measurements at the 5.9 GHz ITS band and present detailed T2I propagation channel evaluations which are actually extracted from the published manuscripts [4, 5, 6, 14].

4. What specific improvements should the authors consider regarding the methodology? What further controls should be considered? One detailed flow chart is needed to clarify the readers about flow of research with each stage. Mathematical equations need justification with each stage. Section 3.3. Measurement Settings and Scenarios need further illustrations.

5. Are the conclusions consistent with the evidence and arguments presented and do they address the main question posed? Conclusion section needs revision with more technical facts in the precise way aligned with the result section only.

6. Are the references appropriate? This section is also need revision with more references from recent years.

7. Please include any additional comments on the tables and figures. One table should be added in the literature review section. Further, table should be added in the result section to compare the work of published articles with the current manuscript.

 

Minor editing of English language required

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

The article focuses on the DSRC communications to facilitate the reduction of the number of accidents between vehicles and trains, this is indeed an interesting topic, but it is certainly not treated sufficiently extended to create a sufficiently good emergence and exposure for the reader and the literature of specialty.

The introduction must contain a broad presentation of statistics regarding deaths and the number of people injured in road and railway accidents, but also the exposition of some issues on which this idea is based.

Another observation is that some scenarios that are the basis of road accidents should be exposed, their outline and illustration would bring a sufficiently visible gain to the article.

The introduction is not comprehensive and does not have a scientific form, 2-3 pages are recommended to present the most important things we know about the studied subject.

Chapter 2 is also not too far from the first and has insufficient information to be classified as having a good form of publication. Try to analyze current articles, but also related domains solved with systems based on 5.9 DSRC. Systems implemented, but also results presented by those research groups.

Including the case of chapter 2, please rewrite it in its entirety and improve it accordingly, 3-4 pages may be enough,

The naming and formatting of the chapter titles is contrary to the journal template and do not follow its recommendations.

Is the DSRC system made by you? Was an off-the-shelf/commercial system used? Present the complete hardware architecture for better visibility and parameters that give us a perspective.

Compare the characteristics of the designed antenna/system with others already existing to observe latencies, communication distances, speeds, connectivity, coverage, interconnectivity method, sensors used (GPS, GLONASS, Galileo), and their calibration method.

Are the measurements made from point to point on the spot or is there a connectivity interface that specifies the location (GPS coordinates) and the information you obtained?

How has the solution responded to the interference caused by the cables at the level of railway crossings, especially since in those areas there can be attenuated by the railway lines, but also by the respective networks and cables?

Another important aspect is related to train speeds, in developing countries they register speeds of over 140-160 km/h. How does the system behave in conditions of extreme mobility?

Figure 2 is insufficiently detailed and its legend does not have the necessary information for a reader to understand.

How is the coding done? The software application, algorithm? Architecture?

Chapter 3 ends abruptly without much information about what has been achieved and it seems that something is missing. Exposures, data, tables...

Chapter 4 seems incomplete to me, it should have been used for drawing conclusions and analyses based on the results obtained, an aspect that is dealt with in 5.

The article requires a total reorganization and this involves moving several sub-chapters and condensing the information.

The calculations and expositions regarding the results had to be exposed in the methodology so that later on based on the formulas a certain characteristic could be implemented.

The references are insufficient and not all are current.

I have no comments regarding the quality of the English language, maybe there are small adjustments to be made.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

5.9GHz Channel Characterization at Railroad Crossings for Train-to-Infrastructure (T2I) Communications

The authors have addressed almost all the potential concerns; the manuscript may be accepted for publication.

Minor editing of the English language is required, in few places, grammatical revision is required.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

The article has been substantially improved and no omissions are observed, perhaps on the part of the figures you can increase the readability and give them a more professional form, otherwise, the article presents itself well and can move on.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf