LTE/NR V2X Communication Modes and Future Requirements of Intelligent Transportation Systems Based on MR-DC Architectures

Round 1

Reviewer 1 Report

This paper provides an overview of the communication modes and potential requirements in the C-V2X scenario of intelligent transportation system. In simulation, PDR is introduced to evaluate the performance under different configurations. This paper is organized well, but some problems need to be addressed.

 

Comments:

The full name of acronym should be given when the acronym first appeared in the text, even the full name was mentioned in the abstract, such as, “ITS”, “V2X”, “PDR” in the introduction.

“are present” should be “are presented” in line 76.

“… the spectrum requirements for the spectrum needs for the…” in the line 39 has repetition.

“In all cases the reliability of the network must be higher than 90%” in the line 216 indicates the reliability should be higher than 90%. Why is the reliability in Table 2 “90%-90.999%” rather than “90%-99.999%” or “90%-100%”?

The unit “pps” is not introduced. Does it mean “packet per second”?

Similarly, the unit “vpm” should be mentioned after “vehicles per meter”.

Author Response

First of all, the authors would like to thank Reviewer 1 for his/her valuable comments, which have helped a lot to improve the quality of the previous version. Details of the changes made to the paper can be found in the attached document. It specifically indicates the line in the text, table or figure where changes were made in accordance with the observations made.

Author Response File: Author Response.pdf

Reviewer 2 Report

The potential of Third Generation Partnership Project (3GPP) 2 mobile cellular standards is studied to enable vehicular communications in this work.

Comments:

1. The title should be concise to grasp the key proposal of this wok.
2. In Abstract, place the background of this study more clearly is needed.
3. Also in Abstract, please briefly describe the main methods used in this work.
4. The abbreviations can only be mentioned after they defined.
5. The article must include flowchart to explain the processing of developing the results or how the system is working.
6. To provide the definition of notations and abbreviation in the Table is needed.

Author Response

First of all, the authors would like to thank Reviewer 2 for his/her valuable comments, which have helped a lot to improve the quality of the previous version. Details of the changes made to the paper can be found in the attached document. It specifically indicates the line in the text, table or figure where changes were made in accordance with the observations made.

Author Response File: Author Response.pdf

Reviewer 3 Report

The paper addresses a relevant and interesting topics related with V2X communications.

The article is written in a clear fashion and facilitates the reader to gather knowledge on the topic, and some evaluation results are provided to demonstrate the need for MultiRAT technologies towards ITS.

The paper can be improved, by considering:

1. line 22, Expand acronym ITS .
2. line 25, Correct "of transports networks" -> "of transport networks"
3. line 133, remove ac in "acRel-15"
4. Section 4.1, complete the parameters that are included in Table 3, for instance, vehicle density, simulation time.
5. lines 347, 349, 351 remove '.' after names "INET. - [24]." should be INET [24] - an open...". The same applies for VEINS, and SUMO.
6. Section 4.1.1 do not provide information regarding the messages that are exchanged between vehicles. For instance, CAM, frequency, mode of transmission (unicat, groupcast, broadcast).
7. Section 4.1.1. should also have more information regarding the evaluation metrics. Authors only include the Packet Delivery Ratio, but do not present and discuss results regarding other metrics like latency.
8. Section 4.1.2, authors could present results in a better way. Figure s 6, 7 and 8 do not need to have such size, they can be small, assuring readability is kept and Figure 6 and 7 can be placed side-by-side to facilitate discussion and comprehension.
9. lines 399 and 400. Be more objective regarding the idea you mean. "However, for longer distances the percentage of packets that are not received correctly increases." --> to However, longer distances lead to higher packet losses. 
10. Section 4, ending in page 14, clearly demonstrates the need for MR-DC (thank you). The main suggestion is to enhance presentation of results as stated previously.
11. Section 5, Figure 11, can be improved, by choosing another colour in the road to facilitate reading labels. The gray colour does not allow to read the text in black.
12. line 477 add a missing ')'.
13. line 507, 509  provide more info in text and in Figure 12 that facilitates the clear understanding of the differences between NE-DC and NGEN-DC.
14. Improve figure 13, it is hard to read, in particular enhance text size
15. Section 5, could have more information regarding how authors plan to assess the MR-DC in the simulator openCV2X. 

 

Author Response

First of all, the authors would like to thank Reviewer 3 for his/her valuable comments, which have helped a lot to improve the quality of the previous version. Details of the changes made to the paper can be found in the attached document. It specifically indicates the line in the text, table or figure where changes were made in accordance with the observations made.

Author Response File: Author Response.pdf