Research on a Vehicle-Mounted Emergency Communication System Using BeiDou Regional Short Message Communication (RSMC) for Firefighting Operations in Forest Areas without a Public Network

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper is well written and motivates the problem it is addressing (communicating with firefighters in remote forests).

This paper considered a communication system that combines RSMC and a Zigbee local network. The system was tested by simulating a fire and it is was shown that a reliable communication link was established with a remote command center.

In section 2.1.2 I would have liked to see a discussion of the range of Zigbee network links.

As mentioned, another drawback to the tested setup was the lack of different type of geographic locations for testing. This could be stated in the introduction of this paper.

 

 

Author Response

Comments 1: [In section 2.1.2 I would have liked to see a discussion of the range of Zigbee network links.]

Response 1: [Thank you very much for raising this issue. Adding a discussion of zigbee in section 2.1.2 can make the article more convincing.

The communication range of individual Zigbee devices is generally between 10m and 30m, while the distance of the parameter collection nodes with forest fire trucks as carriers is no more than 10m, so the range of the zigbee network link can meet the requirements of local area wireless network. From the outside, through the relay function of zigbee devices and optimised layout, its coverage can be further extended.

We have added the above discussion and Table 1 in section 2.1.2 of the manuscript.]

 

Comments 2: [As mentioned, another drawback to the tested setup was the lack of different type of geographic locations for testing. This could be stated in the introduction of the manuscript.]

Response 2: [Thank you very much for raising this issue. A statement about the lack of different type of geographic locations for testing has been added to the introduction of the manuscript.]

 

We apologise for any distress caused and thank you very much for your help.

Reviewer 2 Report

Comments and Suggestions for Authors

The authors present a mobile communication system for command centers at fire sites. While the work is interesting and they seem to have made significant efforts for the tested scenario, there are some issues that should be addressed to enhance the readership of the work:

Please explain why you opted for Zigbee and not any other LPWAN technology like LoRa or even a typical GSM network module.

Figure 1: Add the Zigbee communication link and ensure all the arrows are bidirectional.

In section 2.4, paragraphs two and three, the phrase "Six stumpage environments were selected for the experiment" is used twice. Please amend accordingly.

All metrics are related to signal quality. Please provide metrics for end-to-end message elapsed time. Also, in the case of a missing packet, how do you handle this situation?

As there is no public network coverage, how do you send signals to the LF1352JP tracked firefighting vehicle to reach the epicenter of the fire? Please elaborate on a complete scenario as this is the main novelty of this work, and it lacks solid reasoning. If there is still public network coverage as stated in section 4, then please justify the need for such a system

 

Author Response

Comments 1: [Please explain why you opted for Zigbee and not any other LPWAN technology like LoRa or even a typical GSM network module.]

Response 1: [Thank you for your advice.

Zigbee technology shows obvious advantages after considering the special needs of forest firefighting vehicle-mounted wireless communication networks. The low power consumption of forest firefighting vehicles, which may operate for tens of hours at a time, allows them to maintain communication networks for long periods of time.

The self-organising nature makes them particularly suitable for emergency fire-fighting operations. If a link fails and does not work, the operator does not have to spend extra time dealing with the problem; it will adjust its topology and find another suitable link on its own.

In addition, the communication range of individual Zigbee devices is generally between 10m and 30m, while the distance of the parameter collection nodes with forest fire trucks as carriers is no more than 10m, so the range of the zigbee network link can meet the requirements of local area wireless network. From the outside, through the relay function of zigbee devices and optimised layout, its coverage can be further extended.

The above and a table comparing various common wireless communication technologies have been added to section 2.1.2 of the manuscript.]

 

Comments 2: [Figure 1: Add the Zigbee communication link and ensure all the arrows are bidirectional.]

Response 2: [Thank you for the correction. Adding Zigbee communication link and ensuring proper arrow direction in Figure 1 makes the system architecture clearer and more comprehensive. Figure 1 has been updated in the manuscript.]

 

Comments 3: [In section 2.4, paragraphs two and three, the phrase "Six stumpage environments were selected for the experiment" is used twice. Please amend accordingly.]

Response 3: [Thank you for the correction.The third paragraph of section 2.4 has been corrected to read as follows.

The LQI can reflect the channel quality of the local self-organizing network. In order to get the LQI, the data of the network’s message packets need to be collected. The experiments measured the number of stumpages per unit area in different environments separately. The distance from the coordinator node to the forest fire truck was increased from 1 to 10 m, the terminal node transmitted 60 packets to the coordinator node every 1 m in the different stumpage environments, and the emberGetLastHopLqi() function was used to parse the LQI of the packets.]

 

Comments 4.1: [All metrics are related to signal quality. Please provide metrics for end-to-end message elapsed time.]

Response 4.1: [Thank you very much for your suggestions. End-to-end time metrics can be important for evaluating system performance in the time dimension.

Iit is important to ensure that reliable communication links are established when conducting firefighting operational processes in forested areas with restricted terrestrial networks. Therefore, the research in this paper focuses on signal quality and system reliability. Furthermore, in previously conducted experiments, the communication latency between Zigbee devices typically ranged from tens of milliseconds to hundreds of milliseconds, with an average latency of approximately 2.8 seconds for RSMC communication. This means that the overall system latency is between 2 seconds and 4 seconds, and the impact of communication latency on system performance is relatively small. Therefore, end-to-end time is not a key research metric in this paper.]

 

Comments 4.2: [Also, in the case of a missing packet, how do you handle this situation?]

Response 4.2: [Thank you very much for your concern about the system's packet loss. I will focus on explaining to you the strategies to deal with packet loss situations in RSMC networks

The communication process of Beidou RSMC is a linkless transmission process similar to UDP, which means he is an unreliable protocol. If the packet is lost or corrupted, it will not do any processing. Therefore we make the following design in the communication process.

We design the timeout retransmission mechanism. When the receiver thread listens to the message, it needs to send an answer frame (ACK) to the sender , indicating that it acknowledges receipt of the message. The sender starts a timer after sending the packet and is ready to retransmit the packet if no acknowledgement or feedback is received within the timeout period. For the case of a missing packet, this can enhance the reliability of short message transmission in wireless environments.]

 

Comments 5.1: [As there is no public network coverage, how do you send signals to the LF1352JP tracked firefighting vehicle to reach the epicenter of the fire? Please elaborate on a complete scenario as this is the main novelty of this work, and it lacks solid reasoning.]

Response 5.1: [Thank you very much for your question. Role A is classified as the firefighting site operator and Role B is the remote command center operator. Here is a complete scenario.

(1) When the fire breaks out, Role B monitors the location of the fire through remote sensing satellite imagery at 45°22′N, 127°30′E;

(2) Actor B sends the fire location and fire fighting instructions to Actor A through the system, and A drives the forest fire truck to the fire scene according to the instructions (there is no ground network signal at this time;

(3) A reports the fire situation to B through the satellite communication link established by the system and fights the fire under the command of B;

(4) Forest fires were extinguished.

Thus, firefighters have completed a fire emergency communication through this system.

We apologise for your query as we did not mention a complete scene in the manuscript. The above scene is added to section 2.3 of the manuscript.]

 

Comments 5.2: [If there is still public network coverage as stated in section 4, then please justify the need for such a system.]

Response 5.2: [Thank you very much for your question. If there is still public network coverage, the system we have designed continues to offer significant advantages and necessities, including:

(1) Emergency backup: terrestrial networks may fail or become unstable in extreme environments (e.g., fires, earthquakes, etc.). Our system serves as a backup for terrestrial network communication and can provide reliable communication guarantee at critical moments;

(2) Data security: In emergency situations, the fire command system needs to transmit a large amount of sensitive data. Through the dedicated communication network of the Beidou satellite navigation system, possible security loopholes in the public network can be avoided to ensure the privacy and integrity of the data.

With these enhancements, our system is not only able to provide reliable communications in the absence of public network coverage, but also significantly improves rescue efficiency and safety in the presence of public network coverage, ensuring the successful completion of fire-fighting missions.]

 

We apologise for any distress caused and thank you very much for your help.

Reviewer 3 Report

Comments and Suggestions for Authors

The content of this paper is comprehensive and well written in describing the architecture and structure from which real test cases have been demonstrated. These include showing the construction and the form at both network and physical layer.

Regarding SNR performance it is worth to note if this had the assmption that there is always a line of sight to the satellite. In forest areas there may be some tree attenuation and this should be commented on and indeed if there is enough SNR margin to accommodate their losses.

Section 2 has two sub headings right underneath it without any text. This isn't a good thing. The section needs a short introduction of one or two sentences, then the same for the sub section 2.1 so there is some flow in the paper.

Simlilarly sectoin 3 needs some introduction.

Author Response

Comments 1: [Regarding SNR performance it is worth to note if this had the assmption that there is always a line of sight to the satellite. In forest areas there may be some tree attenuation and this should be commented on and indeed if there is enough SNR margin to accommodate their losses.]

Response 1: [Thank you very much for your suggestions. It is important to clearly state whether the satellite is in line-of-sight or not. We have added this in the fifth paragraph of section 2.4 of the manuscript. Also, we have added the following clarification in section 3.3:

Due to the special communication environment in forested areas, there is no guarantee that there is always a line of sight to the satellite. Therefore, it is necessary to discuss whether the signal has enough SNR redundancy to compensate for the loss of signal caused by tree shading. For satellite digital communications, an SNR of 10 dB or more is usually required to ensure reliable communications. For the 10 channels shown in Fig. 8, the overall SNR average value of the test is 23.46 dB, then the average SNR redundancy of all channels is 13.46 dB, and the system has enough redundancy to compensate for the loss of signal caused by tree shading.

In addition, we have added the following discussion of line-of-sight propagation and signal SNR margins to the discussion of the manuscript:

In addition, due to the special operating environment in forested areas, shading by trees can cause attenuation of the signal. This attenuation can be affected by leaf morphology and depression, etc. In order to ensure the singularity of the test variables, the experiments were set up so that there is always line-of-sight propagation between the terminal and the satellite, and enough redundancy was left to cope with the loss caused by tree shading. In future studies, we will further analyze the extent of attenuation of the signal caused by factors such as foliage morphology and degree of depression in order to improve the analysis of the system performance.]

 

Comments 2: [Section 2 has two sub headings right underneath it without any text. This isn't a good thing. The section needs a short introduction of one or two sentences, then the same for the sub section 2.1 so there is some flow in the paper.]

Response 2: [Thank you for your suggestions on the structure of the article. We have added a short introduction after sections 2 and 2.1. The introduction has been added to the manuscript.]

 

Comments 3: [Simlilarly sectoin 3 needs some introduction.]

Response 3: [Thank you for your suggestions on the structure of the article. We have added a short introduction after section 3. The introduction has been added to the manuscript.]

 

We apologise for any distress caused and thank you very much for your help.

Reviewer 4 Report

Comments and Suggestions for Authors

Dear Authors,

Thank you for submitting your manuscript titled "Research on a Vehicle-Mounted Emergency Communication System Using BeiDou RSMC for Firefighting Operations in Forest Areas without a Public Network" to the journal Forests. Here are my suggestions for improvement:

1. Improve the grammar and clarity of the English used, potentially with the assistance of professional editing.
2. Structurally, ensure the manuscript is organized into clear sections: Introduction, Methods, Results, Discussion, Conclusion, and References.
3. Aim to make the content more concise by eliminating redundancy and focusing each paragraph on a single idea.
4. Define all acronyms on their first use (e.g., "Regional Short Message Communication (RSMC)") and use them consistently afterward.

Best regards,

 

Comments on the Quality of English Language

Extensive editing of English language required

Author Response

Comments 1: [Improve the grammar and clarity of the English used, potentially with the assistance of professional editing.]

Response 1: [Thank you very much for your suggestions. For the grammar and clarity of the English used, we have made changes under the guidance of a professional native-speaking editor, such as the abstract section and the conclusion section. The relevant content in the manuscript is updated to the revised version.]

 

Comments 2: [Structurally, ensure the manuscript is organized into clear sections: Introduction, Methods, Results, Discussion, Conclusion, and References.]

Response 2: [Thank you very much for your suggestions. We have revised the structure of the article to Introduction, Methods, Results, Discussion, Conclusion, and References. Revised article structure to update to the manuscript. ]

 

Comments 3: [Aim to make the content more concise by eliminating redundancy and focusing each paragraph on a single idea.]

Response 3: [Thank you very much for your suggestions. We have re-examined all paragraphs and will remove redundancies.

After revisiting the structure of the article, we have revised some paragraphs to make them more concise. For example, the discussion of the different characteristics of each type of wireless communication technology in section 2.1.2, the reclassification of the experimental procedure in section 2.3, and the discussion of the research in section 4 have been revised. The relevant content in the manuscript is updated to the revised version.]

 

Comments 4: [Define all acronyms on their first use (e.g., "Regional Short Message Communication (RSMC)") and use them consistently afterward.]

Response 4: [Thank you very much for your suggestions. We have checked all acronyms appearing in articles to ensure that each abbreviation is defined the first time it appears and that it is used consistently thereafter.The relevant content in the manuscript is updated to the revised version.]

 

We apologise for any distress caused and thank you very much for your help.