DASH Live Broadcast Traffic Model: A Time-Bound Delay Model for IP-Based Digital Terrestrial Broadcasting Systems
Round 1
Reviewer 1 Report
1. The authors give a terrible presentation in the Introduction section. The author only tells us the proposed transmission structure and how to model and analyze it. However, they do not clearly describe the current problem, the related solutions, and why we need the proposed solution.
2. There is already much research on the traffic model of IP-based broadcasting. The author should explain what advantages the proposed model has compared with the past.
3. Although the proposed traffic model is for DASH, the authors do not present DASH characteristics in the IP-based broadcasting network and simplify modeling the network too much.
Author Response
Point 1: The authors give a terrible presentation in the Introduction section. The author only tells us the proposed transmission structure and how to model and analyze it. However, they do not clearly describe the current problem, the related solutions, and why we need the proposed solution.
Response 1:
As you pointed out, I added the contents that describe the current problem, the related solutions, and this paper’s contribution in the Introduction section.
Point 2: There is already much research on the traffic model of IP-based broadcasting. The author should explain what advantages the proposed model has compared with the past.
Response 2:
As you mention, there is already research on the traffic model of IP-based broadcasting. However, I think the target network is different. This paper’s research target is the terrestrial broadcast network. I do not clearly describe before, thank you for your help.
As you pointed out, I added the contents that describe the related research. However, especially in the terrestrial broadcasting networks, despite being a problem due to the fixed resources and the variability of the DASH segment file size, there is no related research about the transmission delay and resource efficiency of the terrestrial broadcast network when transmits DASH segment files.
Point 3: Although the proposed traffic model is for DASH, the authors do not present DASH characteristics in the IP-based broadcasting network and simplify modeling the network too much.
Response 3:
As you mention, this paper does not present DASH characteristics. DASH is proposed due to network fluctuation. However, the target network is the terrestrial broadcast in this paper, and its characteristics are fixed bitrates. Instead, this paper analyses the characteristics of DASH media in section 5.2.2.
You are right about simplifying the modelling. However, simplification for modelling is done in most papers. In this paper, I tried to predict the transmission delay in terrestrial broadcasting. Therefore, some of the values are omitted because of the characteristics of the terrestrial broadcast network.
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
This paper proposes a live broadcast traffic model. It presents the results of resource efficiency and transmission delay that occur when transmitting DASH segment files for a single media transmission. Through the live broadcast traffic model, authors also report the maximum delay time that a viewer accessing the broadcast can experience. Although this paper uses simple and easily-implementable design, this reviewer thinks that some important parts are missing:
- The results (figures) are standalone and the readers do not know how does the proposed model compare to the existing transmission strategies. Baseline data should be added (delay, efficiency), and graphs should compare the proposed method to a legacy method.
- Conclusions are vague. Comparing the measured data with legacy data would also yield a stronger and better conclusion.
- Writing style could be improved, e.g. page2 line 72 "mainly primarily"; start of the sentence in page 2, line 87; page 3 line 94: "the starts transmission starts" etc. The manuscript should be thoroughly proofread and structure of some sentences should be improved.
- There is a mistake in the caption of Table 1: "Mbit/S" -> S is siemens-unit for electrical conductance (s is unit for second). HZ is not an SI unit, Hz is an SI unit for frequency. In addition, this reviewer would suggest putting Mbit/s in the far-left column in order for readers to immediately know that the numbers in the table are Mbit/s values.
- Equations (1)-(5) and (6)-end use variable N for different things. Although it is stated in the paper, this reviewer would suggest to use unique notations paper-wide, and to add a table with all the variables and their explanations.
- Is this the minimal set of constrains? Are all of the constrains necessary, or some could be left out?
Author Response
Point 1: The results (figures) are standalone and the readers do not know how does the proposed model compare to the existing transmission strategies. Baseline data should be added (delay, efficiency), and graphs should compare the proposed method to a legacy method.
Response 1:
I added the contents that describe the related research. However, I think the target network is different. This paper’s research target is the terrestrial broadcast network. I do not clearly describe before, thank you for your help.
Especially in the terrestrial broadcasting networks, despite being a problem due to fixed resources and the variability of the DASH segment file size, there is no related research about the transmission delay and resource efficiency of the terrestrial broadcast network when transmits DASH segment files. So, I think, I can not compare the proposed method to a legacy method, as you mention.
Point 2: Conclusions are vague. Comparing the measured data with legacy data would also yield a stronger and better conclusion.
Response 2:
As I mentioned above, I think, I can not compare with legacy data because the target network is different. The delay is one of the important factors that affect the quality of the user service. If the delay of the media service can be predicted, it greatly helps improve the service quality. So, I think the strength of this paper uses a simple and easily implementable design.
Point 3: Writing style could be improved, e.g. page2 line 72 "mainly primarily"; start of the sentence in page 2, line 87; page 3 line 94: "the starts transmission starts" etc. The manuscript should be thoroughly proofread and structure of some sentences should be improved.
Response 3:
I appreciate your comments. It will help be a better article. I corrected what you mention.
Point 4: There is a mistake in the caption of Table 1: "Mbit/S" -> S is siemens-unit for electrical conductance (s is unit for second). HZ is not an SI unit, Hz is an SI unit for frequency. In addition, this reviewer would suggest putting Mbit/s in the far-left column in order for readers to immediately know that the numbers in the table are Mbit/s values.
Response 4:
I appreciate your comments. It will help be a better article. I corrected what you mention. And there were some parts that I can not write due to space.
Point 5: Equations (1)-(5) and (6)-end use variable N for different things. Although it is stated in the paper, this reviewer would suggest to use unique notations paper-wide, and to add a table with all the variables and their explanations.
Response 5:
You are right. The variable N used equations (6) and (7) has a different meaning form other equations. I made a correction. Thank you for your help.
Point 6: Is this the minimal set of constrains? Are all of the constrains necessary, or some could be left out?
Response 6:
This paper’s research target is the terrestrial broadcast network. So, I think all the constraints of the terrestrial broadcast network characteristic are needed.
Please see the attachment.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
The authors addressed most of my review comments.
Reviewer 2 Report
Authors addressed most of the concerns of this reviewer.
