Analysis of MCP-Distributed Jammers and 3D Beam-Width Variations for UAV-Assisted C-V2X Millimeter-Wave Communications

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The article "Analysis of MCP-distributed jammers and 3D beam-width
 variations for UAV-assisted C-V2X millimeter-wave
 communications" need minor revision to process to the next level.

1) How does the paper model the antenna pattern of the UAV? What assumptions are made regarding beamforming?

2) Could the beamwidth adaptation strategy be extended to multi-UAV scenarios? What challenges might arise?

3) What impact does increasing the 3D beamwidth have on the SINR and coverage probability, according to the findings, and how do the number and density of jammers affect system performance, and what mitigation strategies are suggested?

4) How would you extend the paper’s findings to include path loss and blockage models specific to dense urban areas?

Author Response

Reviewer #1:

The article "Analysis of MCP-distributed jammers and 3D beam-width variations for UAV-assisted C-V2X millimeter-wave communications" needs minor revision to process to the next level.

• How does the paper model the antenna pattern of the UAV? What assumptions are made regarding beamforming?

Response:

Thank you for pointing this out. The following new text in the system model (Sec. 2) is incorporated to address how our paper modeled the antenna pattern of the UAV and what the underlying assumptions.

“This paper modeled the antenna pattern of the UAV by considering a uniform square array antenna of N × N elements. Beamforming assumed high-gain antennas with directional capabilities installed on UAVs to compensate for significant millimeter-wave frequency transmission losses, especially for long-distance and high-bandwidth backhaul communications. Beamforming antenna structures that are small, light, affordable, and appropriate for UAVs with constrained payload capacity are considered for the UAV-assisted C-V2X communications. The UAVs used an identical square antenna arrangement with N × N elements that evenly distribute themselves throughout the x-axis and y-axis directions to provide robust beamforming even when fluctuations are caused by mobility. Beamforming also assumes identical antenna arrays’ power; such an assumption makes it easier to analyze an ideal array dimension, which improves transmission rate without taking the system layout and UAV instabilities into consideration.”

 

2) Could the beamwidth adaptation strategy be extended to multi-UAV scenarios? What challenges might arise?

Response:

The authors would like to bring the attention of the reviewers to the system model (Sec. 2) where it is discussed that our current model exploits multiple UAVs and that all the UAVs are equipped with antennas, considering 3D beamwidth.

The following new text in the system model (Sec. 2) is incorporated to address the impact of beamwidth on the multi-UAV scenario.

“In this work, we assumed that a typical transmitting V-N is allowed to associate and communicate with the recipient V-N either by utilizing infrastructure such as multiple UAVs (e.g., LOS-LAPs or NLOS-LAPs) and MBSs, or without utilizing the infrastructure. LOS UAVs as well as NLOS UAVs both exploit 3D beam-width radiations.”

The underlying assumptions are also discussed in the system model (Sec. 2). Please see comment 1.

 

3) (i) What impact does increasing the 3D beamwidth have on the SINR and coverage probability, according to the findings, and (ii) how do the number and density of jammers affect system performance, and (iii) what mitigation strategies are suggested?

Response:

• The 3D beamwidth has a severe impact on the obtained SINR and coverage probability of the V-Ns according to the findings of this paper. It has been shown in the revised version of the manuscript that when the 3D beamwidth of the antenna is increased due to higher winds, higher atmospheric pressure, or mechanical noise of the UAV rotors, the gain of the receiving antenna and the received power is reduced, which reduces the serving V-N link’s SINR and the coverage probability.

      The following new text in the results and discussion (Sec. 8) is incorporated to address the impact of 3D beamwidth on the system performance.

     

“It is shown in the figure that the coverage probability of the V2L connection and V2N connection decreases in comparison with the V2M connection or V2V connection when the antenna 3D beam fluctuations increase from $\sigma=0^{\circ}$ up to $\sigma=3^{\circ}$ in the network due to strong winds, strong atmospheric pressures, and mechanical noise of the UAV rotors. This is because with higher variations in the beam-width, the power received by the antenna reduces, resulting in a lowering of the obtained SIR and the coverage of the given V2L and V2N links.” (Ref. Fig. 8).

               

“The figure shows that when the 3D beam-width variations of the antenna increase from $\sigma=0^{\circ}$ up to $\sigma=2^{\circ}$, it affects the coverage of the V2L connection and V2N connection, and decreases the coverage of the V2L connection and V2N connection when compared with the V2M connection and V2V connection because higher values of 3D beam-width fluctuations result in lowering the power received by the antenna of the UAV, giving rise to a lesser obtained SIR and coverage of the V2L connection and V2N connection.” (Ref. Fig. 10).

 

• The number and density of jammers in the given region also affects the system performance according to the findings of paper. It has been shown that when the number of jammers and density increases in the network, it increases the overall interference in the network by introducing additional jamming signals, which result in decreasing the SINR, coverage probability and the spectral efficiency of the network.

      The following new text in the results and discussion (Sec. 8) is incorporated to address the effect of number and density of jammers on the system performance.

“The coverage of the V2X connection in the presence of jamming clusters in the region decreases with increasing number of jammers and clusters in the network. This is because a higher value of jammers means that a larger value of jamming interference is introduced in the network, when compared with the V2X link without considering jammers, leading to a reduced obtained SIR and coverage probability for the V2X links considering jamming.”

 

• Following mitigation strategies are suggested to minimize the influence of jamming. The following new text in the mitigating jamming interference (Sec. 7) is incorporated to suggest mitigation strategies that can minimize jamming influence.

“To ensure the safe operation of vehicle networks while dealing with jamming transmitters, a number of strategies can be used to mitigate the negative effects of jamming equipment. Slot-based V2X systems are a potential side-link blocking approach [38] that can be used to lessen several negative effects of organized jamming. The use of deliberate side-link blocking and initiatives to jam V2X exchanges can be reduced by altering the rate at which information is exchanged. A probabilistic-channel browsing technique [39] that aims to react to the blocking disruption may also be employed to lessen the disruption brought on by the clustering process of jammers. The channel surfing technique mostly works by changing the control channel to a distinct channel. Also, an abrupt variation in channels can aid in minimizing the impact of jamming by broadcasting the messages and transmitting the contents on an un-jammed channel, as described in [40]. This strategy helps in reducing the negative effects of jamming. The work in [41] examines a convoy system that uses a behavior-based structure whereby VNs cooperate and exchange addresses to counter jammer assaults in an effort to lessen the interference triggered by jamming devices. Furthermore, in a jamming-disturbed environment, the multiple-input multiple-output-based method suggested in [42] may be applied to analyze the data obtained. In real-world scenarios, the rate-adaptation and power-management techniques outlined in [43,44] can possibly be applied to mitigate the disruptive effects of jamming devices”.

 

4) How would you extend the paper’s findings to include path loss and blockage models specific to dense urban areas

Response:

Thank you for this comment. This paper’s findings can be extended by including path loss and blockage models addressed in [32] for dense urban areas. The following new text in the system model (Sec. 2) is incorporated to address the reviewer’s comments.

 

“An exclusive pathloss approach to millimeter waveband-based connectivity has not yet been defined for remote regions, therefore, a 3GPP’s pathloss model for remote regions is taken into consideration. We assume a millimeter waveband dependent pathloss framework for rural terrain (as presented in) [24,33] and configure the network configurations of rural environment provided by rural macro (RMa), rather than dense urban areas. To analyze the dense urban areas like urban macro (UMa) or urban micro (UMi), the pathloss models presented in [32] for UMa or UMi can be considered. Since UMa and UMi pathloss models are conventionally considered when the base-station height limitations are up to 25 m and 10 m, respectively, whereas RMa base-station heights are up to 150 m, taking RMa into account allows us greater freedom in selecting the base-station altitudes of the considered C-V2X network-assisted by UAVs. The pathloss is expressed for building altitudes, Hb up to 50 m and wireless tower altitudes up to 150 m and is given as follows:”

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript presents a comprehensive quantitative analysis of the negative effects caused by clustered interference and 3D beamwidth fluctuations on the performance of UAV-assisted Wave C-V2X networks. It highlights the critical importance of incorporating advanced anti-interference techniques into network design. This study demonstrates substantial application potential in relevant fields. However, several aspects warrant further refinement:

1. The abstract lacks sufficient specificity. While it mentions the analysis of coverage and spectral efficiency, it does not explicitly detail the simulation parameters employed or provide quantitative descriptions of the results. Including such information is essential to enhance the clarity and persuasiveness of the abstract.
2. Several parameters recurring throughout the manuscript is not clearly defined. Providing precise definitions for these parameters will improve the comprehensibility of the equations and their applications.
3. Errors exist in the derivation from Equation (9) to Equation (10). These miscalculations should be corrected, and all subsequent references to Equation (10) must be updated accordingly.
4. A potential error involving an extraneous 'Z' in the third line of Equation (16) requires verification and correction.
5. The performance degradation of V2V and V2N in Figures 7 and 8 is not significant, which may lead to conclusions that are overly general and insufficiently supported by detailed analysis. Moreover, in Figure 9, only the V2X case is discussed, while the remaining components are not addressed. It is recommended that the authors provide a more comprehensive description and analysis to enhance the credibility of the results.
6. The purpose of the black solid line in Figure 11 is unclear. Please clarify whether this curve serves as a reference under interference-free conditions or if it is solely intended to compare the performance of the V2X link under different interference densities. The design intention should be explicitly stated.
7. The numbering order of Figures 10 and 11 appears to be incorrect. Please check and revise the figure numbers to ensure consistency between the figures and their corresponding references in the text.
8. In Figure 11, only the black V2X and V2M curves exhibit a significant decline, while the other curves remain almost unchanged. The conclusions drawn are rather general. It is recommended to provide a detailed explanation for the lack of noticeable decline in the other curves to strengthen the persuasiveness of the conclusions.

Author Response

Reviewer #2: The manuscript presents a comprehensive quantitative analysis of the negative effects caused by clustered interference and 3D beamwidth fluctuations on the performance of UAV-assisted Wave C-V2X networks. It highlights the critical importance of incorporating advanced anti-interference techniques into network design. This study demonstrates substantial application potential in relevant fields. However, several aspects warrant further refinement:

1. The abstract lacks sufficient specificity. While it mentions the analysis of coverage and spectral efficiency, it does not explicitly detail the simulation parameters employed or provide quantitative descriptions of the results. Including such information is essential to enhance the clarity and persuasiveness of the abstract.

Response:

Thank you for this comment. We have updated the revised version of the manuscript to provide details on simulation parameters in the abstract of the paper. Moreover, we have presented quantitative description of the results in the abstract and section 8.2 to enhance the clarity and persuasiveness of the abstract. The following text in the abstract is incorporated to address the reviewer’s comments.

 

“The results show network performance in terms of coverage and spectral efficiencies by setting V-Ns equal to 3 km$^{-2}$, MBSs equal to 3 km$^{-2}$, and UAVs equal to 6 km$^{-2}$. The findings indicate that the performance of millimeter waveband UAV-assisted C-V2X communications is decreased by introducing clustered jamming in the given region. Specifically, the coverage performance of the network decreases by 25.5$\%$ at -10 dB SIR threshold in the presence of clustered jammers.”

 

1. Several parameters recurring throughout the manuscript is not clearly defined. Providing precise definitions for these parameters will improve the comprehensibility of the equations and their applications.

Response:

Thank you for this comment. We have updated the system model (Sec. 2) in the revised version of the manuscript to precisely define the parameters that will improve the comprehensibility of the equations and applications. Also, the updated version in section 8 describes the simulation parameters in detail.

 

1. Errors exist in the derivation from Equation (9) to Equation (10). These miscalculations should be corrected, and all subsequent references to Equation (10) must be updated accordingly.

Response:

Thank you for this comment. We have removed the miscalculations from eqs. 10, 15, 17, 19, 21, and 47 in the revised version of the manuscript.

 

1. A potential error involving an extraneous 'Z' in the third line of Equation (16) requires verification and correction.

Response:

Thank you for this comment. We have updated the revised version of the manuscript to address extraneous ‘z’ in eq. 16.

 

1. The performance degradation of V2V and V2N in Figures 7 and 8 is not significant, which may lead to conclusions that are overly general and insufficiently supported by detailed analysis. Moreover, in Figure 9, only the V2X case is discussed, while the remaining components are not addressed. It is recommended that the authors provide a more comprehensive description and analysis to enhance the credibility of the results.

Response:

We have updated the manuscript in the revised version of the manuscript to address the reasons for performance degradation of V2V and V2N in figures 7 and 8. We also discuss the remaining cases such as V2M, V2V, V2L, and V2N in figure 9. Thank you.

The following text in the results and discussion (Sec. 8.2) is incorporated to address the reviewer’s comments.

“The V2V connection (pink color line curve) and V2N connection (brown color line curve) show lower performance degradation in the presence of jammers in comparison with the V2M connection and V2L connection in the presence of jammers because for the given network parameters, V2M and V2L connections have higher association probability, which results in lowering the association, SIR and coverage performance of the V2V and V2N connections in the presence of jammers.” (Ref. Fig. 7)

 

“The V2V connection and V2N connection showed lower coverage probability in the presence of jamming when fluctuations of antenna beam-width increase in comparison with the V2M and V2L connections in the presence of jamming because for the considered network parameters, V2M and V2L connections have higher probabilities of association, which results in decreasing the association, SIR and coverage probabilities of the V2V and V2N connections in the presence of jamming.” (Ref. Fig. 8)

 

“The spectral efficiencies of the V2V connection, V2M connection, V2L connection, V2N connection and the overall V2X connection without jammers exceed the respective spectral efficiencies of the V2V connection, V2M connection, V2L connection, V2N connection and the overall V2X connection with jammers because by including jammers in the network, the overall interference in the network increases, resulting in a lowering of the SIR and SE of the V-N links with jammers.” (Ref. Fig. 9)

 

1. The purpose of the black solid line in Figure 11 is unclear. Please clarify whether this curve serves as a reference under interference-free conditions or if it is solely intended to compare the performance of the V2X link under different interference densities. The design intention should be explicitly stated.

Response:

Thank you for this comment. We have updated the manuscript in the revised version of the manuscript to address the purpose of the solid black V2X curve.

The following text in the results and discussion (Sec. 8.2) is incorporated to address the reviewer’s comments.

“The V2X connection without considering jammers (solid black line curve) is solely intended to compare the V2X connection with jammers (dotted-dashed black line curve). It serves as a reference curve (under the given node densities). The SE of the V2X connection with jamming decreases in comparison with the reference curve of V2X as the number of jamming clusters increases in the network. This is because an increased number of jammers provides more jamming interference, resulting in a lower SIR and SE for the relevant jamming links. Similarly, the SE of V2V, V2L, V2N, and V2M connections with jamming decreases (in dotted-dashed line curves) when compared with their respective reference SE results (in solid line curves).”

 

1. The numbering order of Figures 10 and 11 appears to be incorrect. Please check and revise the figure numbers to ensure consistency between the figures and their corresponding references in the text.

Response:

The numbering order of the figures is corrected. Thank you.

 

1. In Figure 11, only the black V2X and V2M curves exhibit a significant decline, while the other curves remain almost unchanged. The conclusions drawn are rather general. It is recommended to provide a detailed explanation for the lack of noticeable decline in the other curves to strengthen the persuasiveness of the conclusions.

Response:

Thank you for this comment. We have updated the manuscript in the revised version of the manuscript to address detailed explanation for the lack of decline in the other curves to strengthen the persuasiveness of the conclusions.

The following text in the results and discussion (Sec. 8.2) is incorporated to address the reviewer’s comments.

“The V2X and V2M connections with jamming exhibit a significant decline in SE performance in comparison with the jamming curves of V2V connection, V2L connection, or V2N connection. This is because V-N associates at higher probability with MBS in V2M connection for the considered simulation parameters. Since the association of the V-N with the MBS has a higher probability, thus, when the jammers are introduced in the network, a higher degradation in the SE is observed for the V2M connection. Moreover, since V2X connection’s performance is mainly dependent on the V2M connection, when V2M performance decreases (for the considered simulation parameters), it also accounts for the decrease of the whole system’s SE (i.e., decrease in SE of the V2X connection). Also, the other connections like V2V, V2L, and V2N have lower probabilities of association and coverage in comparison to V2M connection, therefore, the influence and decline of jamming is less noticeable. ”

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

In this manuscript, the authors proposed an Analysis of MCP-distributed jammers and 3D beam-width variations for UAV-assisted C-V2X millimeter-wave communications. The research is interesting and seems novel,  the manuscript's organization is satisfactory, and enough papers have been reviewed and studied. However, some issues must be addressed.
1. In the Abstract section, authors should define the research gaps and novelty.
2. In the introduction, the authors assume that jamming devices are distributed uniformly within a cluster of circular radius. Doesn't this assumption limit the research problem?
3. Table 2 shows the network parameters. How were these optimal values obtained? By chance or any specific method?
4. Some equations' derivation should be transferred to the Appendix section. This helps the readers to follow the research concepts without getting involved in proving mathematical Equations.
5. Authors should compare their proposed method with some state- of- the art models.
6. Authors should clearly explain their proposed method's innovation and superiority over existing approaches.
7. In section 7, the authors should determine the details of the Monte Carlo configurations and the hardware features of the simulation environments.
8. The vertical axis captions should be determined and labeled in figures 5, 6, 7, 8, and 10.
9. The authors should provide a discussion section to analyze their method and the reasons behind its superiority over similar methods.
10. The overheads and limitations of the proposed method should be determined.
11. In section 7, providing some performance metrics helps validate the proposed method and its performance.
12. In the conclusion section, adding future directions helps readers extend the research.

Author Response

Reviewer #3:

In this manuscript, the authors proposed an Analysis of MCP-distributed jammers and 3D beam-width variations for UAV-assisted C-V2X millimeter-wave communications. The research is interesting and seems novel,  the manuscript's organization is satisfactory, and enough papers have been reviewed and studied. However, some issues must be addressed.
1. In the Abstract section, authors should define the research gaps and novelty.

Response:

Thank you for this comment. We have updated the manuscript in the revised version of the manuscript to address research gaps and novelty in the abstract of the paper. The following text in the abstract is incorporated to address the reviewer’s comments.

“The impact of clustered jamming has not been investigated previously for an unmanned aerial vehicle (UAV)-assisted cellular-vehicle-to-everything (C-V2X) communications by considering multiple roads in the given region. Also, exploiting three-dimensional (3D) beam-width variations for a millimeter waveband antenna in the presence of jamming for vehicular node (V-N) links has not been evaluated, which influences the UAV-assisted C-V2X system’s performance. The novelty of this paper resides in analyzing the impact of clustered jamming for UAV-assisted C-V2X networks and quantifying the effects of fluctuating antenna 3D beam-width on the V-N performance by exploiting millimeter waves. To this end, we derive the analytical expressions for coverage of a typical V-N linked with a line-of-sight (LOS) UAV, non-LOS UAV, macro base-station (MBS), or recipient V-N for UAV-assisted C-V2X networks by exploiting beam-width variations in the presence of jammers.”

2. 
   In the introduction, the authors assume that jamming devices are distributed uniformly within a cluster of circular radius. Doesn't this assumption limit the research problem?

Response:

Thank you for this comment. The following text in the system model (Sec. 2) is incorporated to address the reviewer’s comments on the uniform distribution of jammers.

“The jamming devices are distributed uniformly within a cluster of a circular radius. This is because, for the clustered jamming, the system modeling of jammers considers that the jammers are distributed according to an MCP. It is not limiting the research problem in the sense that the size of the radius of the cluster can be increased or decreased to account for the realistic nature of jammers, which are typically present in clusters in the real-world scenario. Moreover, the uniform distribution of jammers facilitates the fact that a typical jammer can be present anywhere in a cluster with a uniform probability.”

3. 
   Table 2 shows the network parameters. How were these optimal values obtained? By chance or any specific method?

Response:

Thank you for this comment. The choice of network parameters facilitates the fact that most of the outcomes of the analysis are quantified in terms of coverage and SE. The network parameters are set by following the specific method given in [11,16] It should be noted that Figs. 3-11 are analyzed by fixing network parameters according to Table 2 unless and until mentioned. For instance, the x-axis of Figs. 3-11 varies but the remaining network settings are unchanged.

The following text in the results and discussion (Sec. 8) is incorporated to address the reviewer’s comments on the network parameters.

“The choice of network parameters facilitates the fact that most of the outcomes of the analysis are quantified in terms of coverage and SE. The network parameters are set by following the specific method given in [11,16].”

 

4. 
   Some equations' derivation should be transferred to the Appendix section. This helps the readers to follow the research concepts without getting involved in proving mathematical Equations.

Response:

Thank you for this comment. Most of the equations in section 6.2 are transferred to the Appendix section to help the readers follow the research concepts without getting involved in proving mathematical equations.

5. 
   Authors should compare their proposed method with some state- of- the art models.

Response:

Thank you for pointing out this. The following text in the introduction (Sec. 1.2) is incorporated to address the reviewer’s comments on comparing our method with some state-of-the-art models.

 

“Our work is different than the state-of-the-art in the following.

• The work presented in [11] considers a C-V2X network that evaluates the association probability, coverage probability, and rate performance of the V-N. However, our investigated setup considers a UAV-assisted C-V2X network that leverages UAVs and MBSs by considering a millimeter-wave antenna and evaluates association, coverage, and SE of the V-N.
• The work presented in [16] considers a UAV-assisted cellular network that leverages LOS UAVs, NLOS UAVs, and MBSs. However, the work does not consider vehicular communications in the presence of jammers. Our method evaluates UAV-assisted C-V2X communications, exploiting jamming and millimeter-wave antennas.
• The work presented in [29] considers UAV-assisted C-V2X communications and evaluates bandwidth efficiency. However, the work does not consider jamming interference as well as 3D beamforming millimeter-wave antennas. Our analysis considers millimeter-wave antennas for UAV-assisted C-V2X communications by exploiting clustered jamming and evaluates association probability, coverage probability, and SE of the network. Also, our setup investigates the effect of 3D antenna beam-width variations on the system’s efficiency.”

6. 
   Authors should clearly explain their proposed method's innovation and superiority over existing approaches.

Response:

Thank you for pointing out this. The following text in the introduction (Sec. 1.2) is incorporated to address the reviewer’s comments on how our work has superiority over existing methods.

 

“Our work is different than the state-of-the-art in the following.

• The work presented in [11] considers a C-V2X network that evaluates the association probability, coverage probability, and rate performance of the V-N. However, our investigated setup considers a UAV-assisted C-V2X network that leverages UAVs and MBSs by considering a millimeter-wave antenna and evaluates association, coverage, and SE of the V-N.
• The work presented in [16] considers a UAV-assisted cellular network that leverages LOS UAVs, NLOS UAVs, and MBSs. However, the work does not consider vehicular communications in the presence of jammers. Our method evaluates UAV-assisted C-V2X communications, exploiting jamming and millimeter-wave antennas.
• The work presented in [29] considers UAV-assisted C-V2X communications and evaluates bandwidth efficiency. However, the work does not consider jamming interference as well as 3D beamforming millimeter-wave antennas. Our analysis considers millimeter-wave antennas for UAV-assisted C-V2X communications by exploiting clustered jamming and evaluates association probability, coverage probability, and SE of the network. Also, our setup investigates the effect of 3D antenna beam-width variations on the system’s efficiency.”

Moreover, our proposed method’s innovations are described below:

The novelty of our proposed method lies in the way we develop our model’s framework that considers multiple V-Ns distributed along multiple roads randomly, and V-Ns are allowed to communicate with the recipient V-Ns either by utilizing infrastructure (such as LOS UAVs, NLOS UAVs, MBSs) or without utilizing infrastructure (such as in V-N to V-N communications), which has not been evaluated in the previous literature. Moreover, our proposed setup considers the impact of clustered jamming on V-Ns links, such as V-N to V-N link, V2M link, V2L link, and V2N link. Also, the influence of 3D beam-width variations along with the clustered jamming is analyzed on the network’s efficiency.”

7. 
   In section 7, the authors should determine the details of the Monte Carlo configurations and the hardware features of the simulation environments.

Response:

Thank you for this comment. We have updated the manuscript in the revised version (section 7 is updated to section 8) of the manuscript to address the details of the Monte Carlo configurations and the hardware features of the simulation environments.

The following text in simulation setup and limitations (Sec. 8.1) is incorporated to address the reviewer’s comments.

 

“Monte Carlo simulations are obtained to validate the analysis. For each of the Monte Carlo independent trials, the MBSs are allocated in the given 2D space based on a 2D PPP with an average value of MBSs given as $\lambda_M$, while the V-Ns are allocated on each of the roads based on a PLP. The average number of roads is given as $\lambda_R$, and the average number of V-Ns on each road, based on a 3D PPP, with an average value of LAPs given as $\lambda_U$. The jammers are distributed using an MCP such that the number of clusters in the given region is a 2D PPP with an average number of clusters given in the region as $\lambda_J$. For each of the clusters, the number of jammers is a Poisson random variable with a mean number of jammers in each cluster given as $J$. The jammers are distributed around each cluster center with a circular radius given as $r_J$. For UAV-assisted C-V2X communications, the performance of the V-N is computed in terms of coverage and SE by assuming that for each of the Monte Carlo trials, a transmitting typical V-N wants to communicate with the recipient V-N located at the origin either by utilizing infrastructure such as multiple UAVs (e.g., LOS-LAPs or NLOS-LAPs) and MBSs, or without utilizing the infrastructure (such as in V-N to V-N communications).”

 

“The simulation results are obtained on MATLAB software using 100,000 Monte Carlo runs by considering hardware, i.e., Intel (R) Core (TM) i7-12700 (20 CPUs), 2.1 GHz, with 16 GB RAM.”

 

8. The vertical axis captions should be determined and labeled in figures 5, 6, 7, 8, and 10.

Response:

Thank you for this comment. We have updated the vertical axis labels of the figures (e.g., Figs. 3, 5, 6, 7, 8, and 10) in the revised version of the manuscript.

9. 
   The authors should provide a discussion section to analyze their method and the reasons behind its superiority over similar methods.

Response:

Thank you for pointing out this. Please note that we present a new subsection in section 8 where we discuss the outcomes of the results (i.e., Sec. 8. 2). The major reasons behind the superiority of our work are mentioned in the discussion section of figures (highlighted red text in Sec. 8. 2).

10. 
    The overheads and limitations of the proposed method should be determined.

Response:

Thank you for this comment. We have updated section 8 in the revised version of the manuscript.

The following text in the subsection, simulation setup and limitations (Sec. 8.1) is incorporated to address the reviewer’s comments.

 

“The main limitation of our proposed method is based on the fact that our system model is developed for a half-duplex network and, therefore, the bandwidth efficiency is lower than a full-duplex vehicular network, where the bandwidth approaches twice the bandwidth of a half-duplex vehicular network. Another limitation of our model is maintaining backhaul connectivity and synchronization in the presence of LOS and NLOS UAVs without affecting the bandwidth efficiency. Moreover, since UAVs are vulnerable to security attacks, it is difficult to maintain a stable and secure platform for UAV-assisted C-V2X communications. Also, one of the main challenges is to lower the control and signaling overheads during base station handovers.”

11. 
    In section 7, providing some performance metrics helps validate the proposed method and its performance.

Response:

Thank you for this comment. We have updated section 6 heading in the revised version of the manuscript to show performance metrics that help validate the proposed method and its efficiency.

 

 

 

12. In the conclusion section, adding future directions helps readers extend the research.

Response:

Thank you for this comment. We have updated the conclusion section in the revised version of the manuscript to address future directions to help readers extend the research.

The following text in the conclusion (Sec. 9) is incorporated to address the reviewer’s comments.

 

“The future directions to extend this research include designing advanced anti-jamming techniques to reduce the impact of clustered jamming on the vehicular communications. This research can also be extended to investigate a full-duplex environment for UAV-assisted C-V2X networks.”

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The authors addressed my concerns and improved their work. So I suggest accepting the manuscript.