----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Reviews Round 2: Reviewer: 1 Recommendation: Accept Comments: Authors have handled all previous comments satisfactorily. Reviewer: 2 Recommendation: Accept Comments: Note I could not read pages 10,11, and 12 (Blank pages), even with different PDF readers. However, this is not important at this stage. The paper has undergone a significant improvement with, in my opinion, convincing replies to all the comments also by the other Reviewers. It is ready for publication. Reviewer: 3 Recommendation: Accept Comments: The authors have adequately addressed all of the reviewers' comments in my view. As I had noted in my initial review, the quality of their work is high and I recommend that the paper is accepted as is. Reviewer: 4 Recommendation: Accept Comments: Good job with the revised version! I was already in favor of the acceptance of the paper in the 1st round and it only improved in R1. Naturally I keep recommending acceptance. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Reviews Round 1: [Note from the managing editor: As you will see from the enclosed reviews the reviewers found merit in your manuscript, but also pointed out a number of shortcomings that need to be addressed. I must therefore classify your manuscript as REVISE and RESUBMIT. As such, the manuscript, after revision would be sent out to the same reviewers, assuming you decide to revise and resubmit.] Reviewer: 1 Recommendation: Accept With Minor Revision Comments: As mentioned in the review of 3., I am curious about why works in mobile analysis of WLAN/WPAN are omitted. Why is this important? Even though the authors limit the scope of mobile traffic analysis in the Introduction, I find the title of the manuscript can be misleading. In this scope proposed by the authors, shouldn't the title be "Large-scale Mobile traffic analysis" or "Cellular traffic analysis"? I understand that a generalized title will be much more convincing, but I get a impression that the title can be somewhat misleading. The OUTLOOK section can be improved if each categories were further organized into subcategories and hierarchically listed. Otherwise, the open problems and issues don't clearly stand out. Additional Questions: 1. Please provide a one-paragraph description of the content of this manuscript.: This survey makes a comprehensive analysis of the literature related to mobile traffic analysis. Mobile traffic, as characterized in the paper, focuses on vast sets of mobile data usage and call profiles collected by various network around the world. The authors exploit three main categories of mobile traffic analysis: social, mobility, and network analysis. Also, authors discuss future open issues and technological enhancements that can be considered through this work. 2. Please identify and discuss the contribution of this manuscript. Please include in your discussion items such as the following:
a. Does the paper have significant tutorial content? That is, is there enough background provided so that the generalist in communications can understand its main contributions? Elaborate.
b. Does the paper contain original contributions? What is the nature of the contributions?
c. Is there a description of lessons learned that are given to the reader to help the reader avoid pitfalls in his own work?
d. Is there a need for a paper such as this in the communications community? For example, are there articles that are already available which cover more or less the same topic at about the same depth?: This survey makes a comprehensive research on the existing literature of mobile traffic analysis. They also make a clear point on their scope, limiting the survey to studies made on large data traffic sets collected by mobile service operators. The taxonomy of the mobile data traffic analysis is very interesting and unique compared to existing work, which allows the reader & reviewer to view this field of area in another interesting point of view. The authors also clearly differentiate the general overview of each work with the technological issues, which allows the readers of all kinds to approach the work and study this area to their fitting. This area of research is very important and relatively new, and can be considered a vital part of communications community. In the point of view that communications technology can also help in various areas of social, epidemiology, transportation, etc, it even makes this survey more intriguing. 3. Please discuss the quality of the citations in this manuscript. If you think the citations should be improved, please provide specific references or sources of articles, such as journals or magazines, that should be consulted. : The quality of citations is good. They have referenced the major works in this field of research. Below are some of the references that are not made in the manuscript but I find relevant to this area. I would like to ask the authors if there are specific reasons why they are omitted or considered out of scope, and if there are no strong reasons to include them 1) P Roy, A.J Martinez, G Miscione, M.H.P Zuidgeest, and M.F.A.M van Maarseveen. Using social network analysis to profile people based on their e-communication and travel balance. Journal of Transport Geography, 24:111 122, 2012. 2) Maxime Lenormand and et al. Cross-checking di erent sources of mobility information. PLoS ONE9 online publication, 2014. 3) Sahar Hoteit, Stefano Secci, Stanislav Sobolevsky, Guy Pujolle, Carlo Ratti, "Estimating Human Trajectories and Hotspots through Mobile Phone Data", Computer Networks, Vol. 64, pp: 296-307, May 2014. 4) Tao Jia, Bin Jiang, Kenneth Carling, Magnus Bolin, and Yifang Ban. An empirical study on human mobility and its agent-based modeling. Journal of Statistical Mechanics: Theory and Experiment, P11024(11), 2012. One thing I would like the authors to clarify is that "Why is most of the literature considering cellular mobile datasets?" 5) Filipe Meneses and Adriano Moreira. Large scale movement analysis from wi-fi based location data. 2012 International Conference on Indoor Positioning and Indoor Navigation, 2012. Are there not some literature that collects various usage/data information from WLAN and WPAN? Are these works out of scope? Or is it that these works are not yet mature compared to cellular? Are there works that utilize vast number of SDN-based WLAN systems to collect information from mobile users? These works also seem relavent. 4. Please comment on the organization of the paper, and offer any suggestions that you think will improve the paper and its readability.: The overall organization of the paper is well-made, and the taxonomy of works shown in Fig. 3 is easily understandable. Using this taxonomy, the sub-categories and lists of paper are straight-forward. However, from the reviewer's point of view, the survey lacks emphasis on historical importance and chronogical organization. 1) It will be really nice if the authors can briefly summarize the history on WHY this area has become important, and why everyone started studying it. 2) The survey is very comprehensive in that it categorizes many researches into three key areas and several sub-categories. However, the researches are not smoothly explained in a chronological manner. Why is this not done? Is it because of the property of the research that there is no gradual chronological improvement in the technology? Or is it that the author's think current organization is better? My point of view is that even though the paper is organized well in the point of different subjects and categories, it is difficult to see how this field of research has made gradual improvements, and how it evolved over time. 5. Please comment on the technical correctness of the manuscript in general, identify any specific technical inaccuracies that you find, and make suggestions for correcting those.: There are no critical technical flaws in the work. 6. If the manuscript does not require major revision, please provide a list of minor changes, such as spelling or grammatical errors, that need to be made. Please use the format 'p. 7., l. 18 somth ==> smooth' to mean 'on line18 of page 7, correct the spelling from somth to smooth.': The manuscript is well written. I found some mistakes: p. 33., reference [134], Syndney ==> Sydney p. 28., l. 10 user.101. ==> user101. Fig.3 should be in front of TABLE 1. 7. Please provide a summary comment on the overall suitability of the paper for publication in IEEE Communications Surveys and Tutorials, assuming the recommended revisions are made. For example, if this is an outstanding contribution, please so state. If a major revision is needed, please so state. If the manuscript requires major editing, please so state.: I believe this is an outstanding contribution to the IEEE Communications Surveys and Tutorials. As shown in this manuscript, the field of mobile traffic analysis has been hot during the past 8-10 years. This survey is clearly very thorough and indicates what kinds of research has been made. Also, it indicates that there are still many future topics that need to be discussed, which shows the potentials of this research field in the area of communications. Reviewer: 2 Recommendation: Revise And Resubmit Comments: 1. The article provides a good taxonomy on existing works on mobile traffic analysis, but it doesn't provide enough comparisons and insights of works in the same category. 2. There should be a comparison table for each important category of works. Right now authors mostly sequentially describe what has been done in each piece of work. This does not give readers vivid differences between these works. 3. The abstract should be completely written. It now tells what to be covered instead of key findings in this survey. Instead of talking about what readers will see, highlight key observations on mobile traffic analysis. 4. Section III should be merged into Section I since it is a part of introduction in its nature. 5. Section II should be made more related to the rest of the article. Right now it appears to be quite independent without good correlation with the other sections. 6. Section VII give open less-investigated issues. The authors could strengthen this section by more of their observations and opinions. Additional Questions: 1. Please provide a one-paragraph description of the content of this manuscript.: The survey first reviews mobile data collection. Then it surveys existing papers in three categories: social analysis, mobility analysis, and network analysis. 2. Please identify and discuss the contribution of this manuscript. Please include in your discussion items such as the following:
a. Does the paper have significant tutorial content? That is, is there enough background provided so that the generalist in communications can understand its main contributions? Elaborate.
b. Does the paper contain original contributions? What is the nature of the contributions?
c. Is there a description of lessons learned that are given to the reader to help the reader avoid pitfalls in his own work?
d. Is there a need for a paper such as this in the communications community? For example, are there articles that are already available which cover more or less the same topic at about the same depth?: a. It provides a good taxonomy of existing works. b. There is no original contribution. In fact, there could be more original observations and comparisons. c. In Section VII, there are some lessons but not enough. d. There are two other survey papers. This one is the 3rd. It covers more existing works, but needs much enhancement so that readers could benefit from it. 3. Please discuss the quality of the citations in this manuscript. If you think the citations should be improved, please provide specific references or sources of articles, such as journals or magazines, that should be consulted. : There are enough citations. Some of them could be screened out if not that important. 4. Please comment on the organization of the paper, and offer any suggestions that you think will improve the paper and its readability.: 1. Section III should be merged into Section I since it is a part of introduction in its nature. 2. Section II should be made more related to the rest of the article. Right now it appears to be quite independent without good correlation with the other sections. 3. In Sections IV, V, VI, there should tables of comparison on important category to compare the major differences of existing works in that category. 4. Section VII give open less-investigated issues. The authors could strengthen this section by more of their observations and opinions. 5. Please comment on the technical correctness of the manuscript in general, identify any specific technical inaccuracies that you find, and make suggestions for correcting those.: Appears to be correct, but didn't check completely. 6. If the manuscript does not require major revision, please provide a list of minor changes, such as spelling or grammatical errors, that need to be made. Please use the format 'p. 7., l. 18 somth ==> smooth' to mean 'on line18 of page 7, correct the spelling from somth to smooth.': 1. P4 line 14 on the right-hand column: "On the other hand, however" have been used in a duplicate way. 2. P17 line 11 on the right-hand column: There seems an error in "show that mobile data can, e.g., help". 3. P19 line 22 on the right-hand column: A typo: "sucess" should "success". 7. Please provide a summary comment on the overall suitability of the paper for publication in IEEE Communications Surveys and Tutorials, assuming the recommended revisions are made. For example, if this is an outstanding contribution, please so state. If a major revision is needed, please so state. If the manuscript requires major editing, please so state.: It could provide a good survey value if it goes through a heavier revision process. Reviewer: 3 Recommendation: Accept Comments: The paper is well-written and organized, and the authors have conducted an impressive amount of work. As explained in my comments above, my basic reservation is that due to its necessarily non-technical and generic nature the survey is borderline in terms of its compatibility with COMST. Still, the fact that it points towards such a large number of research fields and discusses a few works within its field to offer the reader a basic idea of research work and challenges and give valuable references, makes me lean towards its acceptance. Additional Questions: 1. Please provide a one-paragraph description of the content of this manuscript.: The authors provide an exhaustive survey on a large number of research areas associated with mobile traffic analysis. They start with details on the mobile data collection process and move on to discuss how mobile traffic analysis has been used in the literature in regards to social, mobility and networking analysis, and a vast number of subareas within each of these larger areas. They also discuss possible future research directions. 2. Please identify and discuss the contribution of this manuscript. Please include in your discussion items such as the following:
a. Does the paper have significant tutorial content? That is, is there enough background provided so that the generalist in communications can understand its main contributions? Elaborate.
b. Does the paper contain original contributions? What is the nature of the contributions?
c. Is there a description of lessons learned that are given to the reader to help the reader avoid pitfalls in his own work?
d. Is there a need for a paper such as this in the communications community? For example, are there articles that are already available which cover more or less the same topic at about the same depth?: The paper covers a vast amount of related research on the subject, therefore the reader can find out how important mobile traffic analysis is in very diverse areas. The survey more than adequately extends previous surveys in the field, which are properly referenced. However, because of the large number of studies that the authors discuss in each sub-field, they often conclude that the results presented in those studies lead to very diverse conclusions. Hence, this survey may certainly be useful in terms of providing a large number of references for each of its subjects, but in many cases the interested user is left without a clear indication of which research path is best to follow and which pitfalls should be avoided. 3. Please discuss the quality of the citations in this manuscript. If you think the citations should be improved, please provide specific references or sources of articles, such as journals or magazines, that should be consulted. : The citations are adequate. 4. Please comment on the organization of the paper, and offer any suggestions that you think will improve the paper and its readability.: The paper is well-organized. 5. Please comment on the technical correctness of the manuscript in general, identify any specific technical inaccuracies that you find, and make suggestions for correcting those.: I did not find technical inaccuracies. 6. If the manuscript does not require major revision, please provide a list of minor changes, such as spelling or grammatical errors, that need to be made. Please use the format 'p. 7., l. 18 somth ==> smooth' to mean 'on line18 of page 7, correct the spelling from somth to smooth.': Abstract: "apart a few outliers" -> "apart from a few outliers" Introduction: "there exists only two... previous effort" -> "there exist only two... previous efforts" 7. Please provide a summary comment on the overall suitability of the paper for publication in IEEE Communications Surveys and Tutorials, assuming the recommended revisions are made. For example, if this is an outstanding contribution, please so state. If a major revision is needed, please so state. If the manuscript requires major editing, please so state.: The paper is well-written and organized, and the authors have conducted an impressive amount of work. As explained in my comments above, my basic reservation is that due to its necessarily non-technical and generic nature the survey is borderline in terms of its compatibility with COMST. Still, the fact that it points towards such a large number of research fields and discusses a few works within its field to offer the reader a basic idea of research work and challenges and give valuable references, makes me lean towards its acceptance. Reviewer: 4 Recommendation: Accept Comments: No further comments. Additional Questions: 1. Please provide a one-paragraph description of the content of this manuscript.: The paper provides a thorough survey on the analysis of mobile traffic based on mobile phone datasets. 2. Please identify and discuss the contribution of this manuscript. Please include in your discussion items such as the following:
a. Does the paper have significant tutorial content? That is, is there enough background provided so that the generalist in communications can understand its main contributions? Elaborate.
b. Does the paper contain original contributions? What is the nature of the contributions?
c. Is there a description of lessons learned that are given to the reader to help the reader avoid pitfalls in his own work?
d. Is there a need for a paper such as this in the communications community? For example, are there articles that are already available which cover more or less the same topic at about the same depth?: The paper has significant tutorial content, begin perfectly accessible for a generalist in the field. The paper provides a thorough survey in mobile traffic analysis, being complementary to previous surveys in the area. The paper discusses open issues. This is a nice contribution on an area that is quite active in the last few years 3. Please discuss the quality of the citations in this manuscript. If you think the citations should be improved, please provide specific references or sources of articles, such as journals or magazines, that should be consulted. : The paper offers a vast set of related publications covering the whole area. A paper that appeared recently (after the submission), but that may deserve a citation in a final version of the survey is this one: From seconds to months: multi-scale dynamics of mobile telephone calls Jari Saramaki, Esteban Moro http://arxiv.org/abs/1504.01479 4. Please comment on the organization of the paper, and offer any suggestions that you think will improve the paper and its readability.: The paper is well organized 5. Please comment on the technical correctness of the manuscript in general, identify any specific technical inaccuracies that you find, and make suggestions for correcting those.: The paper seems to be technically correct. 6. If the manuscript does not require major revision, please provide a list of minor changes, such as spelling or grammatical errors, that need to be made. Please use the format 'p. 7., l. 18 somth ==> smooth' to mean 'on line18 of page 7, correct the spelling from somth to smooth.': No minor typo spotted 7. Please provide a summary comment on the overall suitability of the paper for publication in IEEE Communications Surveys and Tutorials, assuming the recommended revisions are made. For example, if this is an outstanding contribution, please so state. If a major revision is needed, please so state. If the manuscript requires major editing, please so state.: The paper provides a thorough survey on the analysis of mobile traffic based on mobile phone datasets. This is an area of active research in the last years and is finding multidisciplinary applications. In this sense, this paper offers a nice, well-structured, and general survey to start studying this area that is attracting so much interest.