ICACT20260317 Question.1
Questioner: xueyy@dsp.ac.cn 2026-01-30 오후 4:43:13 |
ICACT20260317 Answer.1
Answer by Auhor pangb@dsp.ac.cn 2026-01-30 오후 4:43:13
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| In this work, the packet success rate (PSR) is estimated based on an empirical path loss model with AWGN and Poisson-distributed burst noise.
In real underwater environments with more complex effects, such as severe multipath, time-varying channels, or non-Gaussian noise, how robust is the proposed FRAB-MAC scheme expected to be?
Are there any plans for sea trials or hardware-based experimental validation? |
The PSR model used here is the same as that in AB-MAC and is mainly adopted to evaluate the effectiveness of the proposed scoring-based reliability factor. At this stage, we do not explicitly consider complex channel effects such as multipath, but the robustness under burst noise has been evaluated in the simulations. Sea trials or hardware experiments are planned as future work, depending on project arrangements. |
ICACT20260317 Question.10
Questioner: shil@dsp.ac.cn 2026-02-09 오전 9:48:07 |
ICACT20260317 Answer.10
Answer by Auhor pangb@dsp.ac.cn 2026-02-09 오전 9:48:07
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| How does FRAB-MAC incorporate reliability into its scheduling objective, and how is the reliability factor (Rs) calculated? |
As shown on slide 15 of the presentation, the new objective function jointly optimizes the reliability factor and the frame length.
The reliability factor is computed using a scoring-based approach.
For each node in the transmission sequence, if either the PSR between the node and the control node, or the PSR between the node and the previous node exceeds a predefined threshold, the node is considered able to reliably receive control information and the reliability factor is increased by one; otherwise, no score is added.
By traversing all nodes in the transmission sequence, we obtain the overall reliability factor of the entire sequence. |
ICACT20260317 Question.11
Questioner: shil@dsp.ac.cn 2026-02-09 오전 9:54:06 |
ICACT20260317 Answer.11
Answer by Auhor pangb@dsp.ac.cn 2026-02-09 오전 9:54:06
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| What is the role of the Fire Hawk Optimizer (FHO) in FRAB-MAC, and how does it improve upon the genetic algorithm used in AB-MAC? |
In our design, FHO is used to solve the scheduling problem by generating a full permutation of nodes and assigning time-slot lengths to each node.
Compared with genetic algorithms, FHO avoids complex operations like crossover and mutation, leading to a shorter computation process and lower complexity.
This allows FHO to converge faster, while its position update mechanism still maintains strong global search ability, resulting in shorter frames and more reliable transmission schedules. |
ICACT20260317 Question.12
Questioner: tranthithanhbg1995@gmail.com 2026-02-09 오전 10:08:50 |
ICACT20260317 Answer.12
Answer by Auhor pangb@dsp.ac.cn 2026-02-09 오전 10:08:50
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| FRAB-MAC is designed for fully connected AUV formation networks. How would the proposed protocol perform, or be adapted, in partially connected or large-scale underwater networks where full connectivity cannot be guaranteed? |
This is a very meaningful question. A fully connected topology is only practical for small formations.For larger formations, we think that a clustering-based approach can be adopted.The clustering mechanism should support dynamic node joining and leaving, and cluster head selection is an important issue that needs to be carefully designed.
We consider this an important direction for our future research. |
ICACT20260317 Question.13
Questioner: tranthithanhbg1995@gmail.com 2026-02-09 오전 10:11:52 |
ICACT20260317 Answer.13
Answer by Auhor pangb@dsp.ac.cn 2026-02-09 오전 10:11:52
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| he reliability factor in FRAB-MAC relies on PSR thresholds between adjacent nodes. How are these thresholds selected, and how sensitive is the protocol performance to different threshold values under varying channel conditions? |
In this paper, our goal is mainly to validate the effectiveness of the proposed score-based reliability factor.
Therefore, the threshold is simply set to 0.5, and we do not conduct a comprehensive performance evaluation of the protocol under different thresholds or channel conditions.Exploring this relationship provides valuable insights for our future work. |
ICACT20260317 Question.14
Questioner: tranthithanhbg1995@gmail.com 2026-02-09 오전 10:14:59 |
ICACT20260317 Answer.14
Answer by Auhor pangb@dsp.ac.cn 2026-02-09 오전 10:14:59
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| Although the Fire Hawk Optimizer shows faster convergence than the Genetic Algorithm in your simulations, how does FHO perform in highly dynamic scenarios with frequent topology changes, and is it suitable for real-time or near real-time scheduling in mobile AUV networks? |
In FRAB-MAC, when an AUV node transmits data, the packet includes its current position information. It also carries future trajectory information, such as the next two planned waypoints. Based on this information, the control node can estimate the present and future PSR by calculating the distance between nodes.We believe this design is well suited for near real-time mobile AUV networks. |
ICACT20260317 Question.15
Questioner: md.t.a.812@ms.saitama-u.ac.jp 2026-02-09 오전 10:51:18 |
ICACT20260317 Answer.15
Answer by Auhor pangb@dsp.ac.cn 2026-02-09 오전 10:51:18
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| What is the main optimization algorithm used by the proposed FRAB-MAC protocol, and what is the main algorithm used by the older AB-MAC protocol it improves upon? |
FRAB-MAC use Fire Hawk Optimizer to solve the optimization problem, and AB-MAC used genetic algorithm. |
ICACT20260317 Question.16
Questioner: md.t.a.812@ms.saitama-u.ac.jp 2026-02-09 오전 10:55:26 |
ICACT20260317 Answer.16
Answer by Auhor pangb@dsp.ac.cn 2026-02-09 오전 10:55:26
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| Besides minimizing frame length, what additional factor does the new objective function in FRAB-MAC consider for improving reliability? |
Besides minimizing frame length, the new objective function in FRAB-MAC also considers a score-based reliability factor.
Specifically, this reliability factor is derived from PSR (Packet Success Rate) and evaluates whether each node in the transmission sequence can reliably receive control information—either directly from the control node or from the preceding node. By jointly optimizing frame length and this PSR-based reliability factor, FRAB-MAC improves the overall reliability of the transmission schedule. |
ICACT20260317 Question.17
Questioner: md.t.a.812@ms.saitama-u.ac.jp 2026-02-09 오전 10:57:50 |
ICACT20260317 Answer.17
Answer by Auhor pangb@dsp.ac.cn 2026-02-09 오전 10:57:50
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| According to the simulation results, what is the key performance improvement (in percentage) that FRAB-MAC achieves in network throughput compared to AB-MAC? |
On average, FRAB-MAC improves throughput by 15.06% compared with AB-MAC. |
ICACT20260317 Question.18
Questioner: arjunvirvashisht@gmail.com 2026-02-10 오전 10:29:20 |
ICACT20260317 Answer.18
Answer by Auhor pangb@dsp.ac.cn 2026-02-10 오전 10:29:20
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| What specific software platform was used for these AUV simulations? |
We run simulations on MATLAB. |
ICACT20260317 Question.19
Questioner: hominpark@etri.re.kr 2026-02-10 오후 7:41:26 |
ICACT20260317 Answer.19
Answer by Auhor pangb@dsp.ac.cn 2026-02-10 오후 7:41:26
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| It is counter-intuitive that the frame length decreased by over 12% despite adding reliability constraints. Is this primarily due to the superior performance of the FHO algorithm itself, or the structural advantage of the redesigned objective function? |
The reduction in frame length results from the combined effect of both the new objective function and the FHO algorithm.
According to the formulations of frame length and the reliability factor, the objective function essentially searches for a permutation that minimizes the sum of distances between adjacent nodes in the transmission sequence.We appreciate this constructive question and plan to conduct ablation studies to further isolate these effects. |
ICACT20260317 Question.2
Questioner: xueyy@dsp.ac.cn 2026-01-30 오후 4:51:07 |
ICACT20260317 Answer.2
Answer by Auhor pangb@dsp.ac.cn 2026-01-30 오후 4:51:07
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| FRAB-MAC relies on a centralized control node for topology discovery and schedule optimization, and the network is assumed to be fully connected.
How would the proposed protocol perform in larger-scale or partially connected AUV networks, such as multi-hop or clustered topologies?
Do the authors see a potential extension of FRAB-MAC toward a semi-distributed or hierarchical scheduling framework? |
FRAB-MAC, as well as AB-MAC and C-TDMA, is designed as a centralized MAC protocol targeting fully connected networks, rather than distributed or multi-hop scenarios. Multi-hop or partially connected networks are therefore beyond the scope of this work.As for large scale network, our simulations have mainly evaluated the impact of network scale, i.e., different numbers of nodes, on throughput performance. |
ICACT20260317 Question.3
Questioner: tanghr@dsp.ac.cn 2026-02-03 오전 10:50:35 |
ICACT20260317 Answer.3
Answer by Auhor pangb@dsp.ac.cn 2026-02-03 오전 10:50:35
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| In the FRAB-MAC protocol, why is the Packet Success Rate (PSR) emphasized when optimizing the transmission sequence? |
We focus on PSR because the goal of this work is to ensure that nodes can reliably receive control messages from the control node. Therefore, it is natural to emphasize the data transmission success probability between two nodes and to select a more reliable recovery link. |
ICACT20260317 Question.4
Questioner: yangyn@dsp.ac.cn 2026-02-03 오전 10:53:30 |
ICACT20260317 Answer.4
Answer by Auhor pangb@dsp.ac.cn 2026-02-03 오전 10:53:30
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| The paper introduces a new objective function that combines frame length minimization with a reliability factor. Why did you choose equal weights (α = β = 0.5) for these components? Was this based on empirical testing or theoretical considerations? |
We used the same weight coefficients primarily to keep the validation simple and to verify whether the reliability factor helps improve the recovery success rate. The choice is empirical, and we can further evaluate the impact of different weight values on protocol reliability in future work. |
ICACT20260317 Question.5
Questioner: tanghr@dsp.ac.cn 2026-02-05 오후 6:23:34 |
ICACT20260317 Answer.5
Answer by Auhor pangb@dsp.ac.cn 2026-02-05 오후 6:23:34
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| What is the main difference between FRAB-MAC and AB-MAC? Does FRAB-MAC completely replace the control information recovery mechanism of AB-MAC, or does it improve upon the existing mechanism? |
FRAB-MAC is an improved version of AB-MAC.
It increases the success rate of the recovery process, and by introducing the Fire Hawk Optimizer, it achieves better frame-length optimization than the genetic algorithm in AB-MAC.
We do not repalce the original control information recovery mechanism; we simply improve it on top of that. |
ICACT20260317 Question.6
Questioner: tanghr@dsp.ac.cn 2026-02-07 오전 10:27:06 |
ICACT20260317 Answer.6
Answer by Auhor pangb@dsp.ac.cn 2026-02-07 오전 10:27:06
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| Why can FRAB-MAC significantly reduce the number of silent nodes? What is the direct relationship between this reduction and the reliability factor Rs? |
FRAB-MAC estimates the packet success rate between nodes and explicitly considers link reliability.
Instead of arbitrarily selecting the next transmitting node, it arranges nodes with higher recovery success probability into the transmission sequence, ensuring reliable communication between consecutive nodes.
As a result, nodes can either directly receive or successfully recover control packets, and a higher reliability factor leads to fewer silent nodes. |
ICACT20260317 Question.7
Questioner: wangsy@dsp.ac.cn 2026-02-07 오전 10:32:15 |
ICACT20260317 Answer.7
Answer by Auhor pangb@dsp.ac.cn 2026-02-07 오전 10:32:15
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| In the case of AUVs high maneuverability and rapid fluctuations in the probability of link delivery, how exactly is the "reliability factor" of FRAB-MAC estimated? |
In FRAB-MAC, when an AUV node transmits data, the packet includes its current position information.
It also carries future trajectory information, such as the next two planned waypoints.
Based on this information, the control node can estimate the PSR by calculating the distance between nodes. |
ICACT20260317 Question.8
Questioner: zhaoyb@dsp.ac.cn 2026-02-09 오전 9:33:10 |
ICACT20260317 Answer.8
Answer by Auhor pangb@dsp.ac.cn 2026-02-09 오전 9:33:10
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| When multiple repair nodes (RNs) concurrently execute rerouting, the paper adopts a latest-first policy. However, in the high-latency environment of acoustic communication, it is difficult to guarantee consistency among nodes. Would this lead to transient routing loops? |
The scenario considered in this paper is not a re-routing scenario after communication failures.
If a node cannot receive its own time-slot information, it remains silent to avoid additional collisions.
Regarding high latency and consistency concerns, our scenario assumes a single collision domain, without multi-hop communication, meaning all nodes are within one-hop reach. |
ICACT20260317 Question.9
Questioner: zhaoyb@dsp.ac.cn 2026-02-09 오전 9:40:34 |
ICACT20260317 Answer.9
Answer by Auhor pangb@dsp.ac.cn 2026-02-09 오전 9:40:34
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| In extreme scenarios where node failures occur frequently, if the rate of new failures exceeds the propagation speed of First-Packet Paving, would the system undergo incessant re-repairs , causing the cumulative Total Path Stretch to become excessively large? |
If a node does not receive the initial control packet, it simply remains silent and skips the current transmission round.The system does not fall into incessant re-repairs, because the control packet sent by the control node explicitly specifies the transmission time slot for each node.Once the current round is completed, a new control node calculates the next frame, and the repair information piggybacked by the last transmitting node only contains the control node ID, rather than the slot duration. |
