Received Signal Strength Indication (RSSI) of 2.4 GHz and 5 GHz Wireless Local Area Network Systems Projected over Land and Sea for Near-Shore Maritime Robot Operations

Round 1

Reviewer 1 Report

In this paper authors present comparison of received signal strength indication (RSSI) between land and sea for 2.4 GHz and 5 GHz Wi-Fi system. The paper is well structured and written, but the impact of the paper is questionable, and contributions do not seem adequate for a journal paper.

 

In section 2 authors describe how the experiments were conducted, but there are several key aspects that weren't mentioned. How was the receiver antenna moved over the sea? Was it on the ship? If yes how does the ship itself influence the signal strength, or do the waves have any influence.

 

From the text, it can be concluded that only one set of measurements was conducted. It would be useful to have at least a pair of measurements to confirm any possible conclusions.

 

In text authors mention mobile robot station, but from the figure 3, it can be seen that a person is pulling the station and that it doesn't have its own drive. For this reason it must not be called a mobile robot station.

 

On page 10 there is one wrong reference ("compiled on Error! Reference source 262 not found..").

Author Response

Thank you very much for your feedback on our manuscript! In response to your feedback, and feedback from other reviewers, we have made the following revisions to the manuscript.

The contributions and impact of the paper was more clearly stated in the abstract and discussion sections in the paper. The experiment description was revised to include more details regarding the data collection process. In particular this includes: sea state and tidal conditions on the day of testing, how distance and RSSI data was recorded, and how the mobile station was moved relative to the ground station. It is accurate that a single set of measurements were collected in the original manuscript. To address this, we recollected data with at least three different data runs for each of the eight experiments. Appendix A was added to the revised paper, which discusses the statistical validity of this revised data (sample size, mean, standard deviation and confidence interval). In addition, hardware modifications were made to improve the experimental data. This includes: employing an access point system with both 2.4 GHz and 5 GHz transmitters to avoid any variability due to differences in access point hardware; the transmitting antenna was mounted on a level-able tripod; and the mobile station tender was pulled on a trailer during the over-land experiments, and driven manually during the over-seawater experiments, to avoid any variability due to differences in the mobile robot station. The wording "mobile robot station" was revised to "mobile station" to alleviate potential confusion. Minor typos addressed.

Reviewer 2 Report

The paper focuses on the study of RSSI over 2.4 and 5 GHz WiFi systems over land and seawater, aiming at comparing these technologies for their adequacy in near-shore transmissions. Overall the paper is well written and clear. The relevance and comparison to related work is well established. However, the characterization of the experimental evaluation needs further improvement. Authors must clearly indicate the size of the data samples, and how many runs were carried out. This is important to understand the significance of the results. In addition, authors should also mention the time (tide condition and roughness of the sea) at which the measurements were taken. This information might be relevant for further works.

Author Response

Thank you very much for your feedback on our manuscript! In response to your feedback, and feedback from other reviewers, we have made the following revisions to the manuscript.

The contributions and impact of the paper was more clearly stated in the abstract and discussion sections in the paper. The experiment description was revised to include more details regarding the data collection process. In particular this includes: sea state and tidal conditions on the day of testing, how distance and RSSI data was recorded, and how the mobile station was moved relative to the ground station. It is accurate that a single set of measurements were collected in the original manuscript. To address this, we recollected data with at least three different data runs for each of the eight experiments. Appendix A was added to the revised paper, which discusses the statistical validity of this revised data (sample size, mean, standard deviation and confidence interval). In addition, hardware modifications were made to improve the experimental data. This includes: employing an access point system with both 2.4 GHz and 5 GHz transmitters to avoid any variability due to differences in access point hardware; the transmitting antenna was mounted on a level-able tripod; and the mobile station tender was pulled on a trailer during the over-land experiments, and driven manually during the over-seawater experiments, to avoid any variability due to differences in the mobile robot station. The wording "mobile robot station" was revised to "mobile station" to alleviate potential confusion. Minor typos addressed.

Round 2

Reviewer 1 Report

By adding additional experiments and explanations authors have improved the quality of the submitted paper.