From mass2008-pc@cs.unibo.it Wed Jun 25 22:19:48 2008 Date: Wed, 25 Jun 2008 22:30:10 -0400 From: mass2008-pc@cs.unibo.it To: Zhongning Chen Cc: Xue Yang , Nitin Vaidya , mass2008-pc@cs.unibo.it Subject: [IEEE MASS 2008] Your paper #1569115377 has been accepted ********** PLEASE READ CAREFULLY THE INSTRUCTIONS BELOW ******** Dear Mr. Zhongning Chen: We are pleased to notify you that your paper #1569115377 ('Dynamic Spatial Backoff in Fading Environments') has been accepted as a REGULAR paper for presentation at MASS 2008 (September 29-October 2, 2008, Atlanta, USA). We received an unexpectedly large number of submissions (over 250)--in addition to about 5 EXTENDED papers, only a very small subset (approx. 26) have been selected as REGULAR papers, based on the reviews and discussions among the reviewers.Congratulations! You will receive more instructions regarding the preparation and submission of the final manuscript in a few days. However, please note that REGULAR papers will be allowed up to 10 pages (in IEEE 10 pt format) in the proceedings (same as original submission limit). Also, some of the regular papers will go through a shepherding process to ensure that they address some of the concerns raised by the reviewers--if your paper is one of these, you will be notified separately at a later time. Thanks for contributing your work to MASS 2008. If you have any additional questions at this point, please feel free to contact us. Looking forward to seeing you at MASS 2008 Sincerely, Sajal K. Das (MASS 2008 Technical Program Chair) Luciano Bononi, Archan Misra and Chunming Qiao (MASS 2008 Technical Program Vice-Chairs) ----------------------------------------------------------------------------- The reviews are below or can be found at http://edas.info/showPaper.php?m=1569115377, using your EDAS login name ======= Review 1 ======= > *** Familiarity: Rate your familiarity with the topic of the paper. Familiar (2) > *** Recommendation: Your overall rating. Weak Accept (4) > *** Contributions: What are the major issues addressed in the paper? Do you consider them important? (Pls. comment explicitly on the relevance of the paper to MASS topics, the technical depth and the importance of the problem addressed.) [Be brief] The major issue addressed is MAC optimization in distributed / ad hoc wireless networks. The contribution is a method to adaptively adjust the carrier sense thresholds of each receiver in a way that, as contended in this submission, allows greater throughput in the network as a whole. The main benefit is seen due to fewer stronger-last collisions (which can cause both packets to be lost). The paper is presented as an improvement upon the work of X. Yang and N.H. Vaidya. > *** Strengths: What are the major reasons to accept the paper? [Be brief] The strengths are that the new algorithm does appear, from the simulation results, to improve upon the throughput of the Yang & Vaidya work. The idea that the fading variance can be used to aid in the optimization of CS threshold and TX rate is a good contribution. The discussion and motivation is good. > *** Weaknesses: What are the most important reasons NOT to accept the paper? [Be brief] The main drawback of the proposed method that the submission does not address is that the distributed algorithm uses a measurement of SINR at the transmitter to estimate what the SINR at the receiver would be. This is flawed because the receiver's ability to receive the message from the transmitter is ONLY a function of the receiver's SINR, not the SINR at the transmitter. It is not clear how well the limited feedback from the receiver used in the proposed method will allow the transmitter to set the CS threshold in terms of the receiver's SINR. Perhaps it should be shown that the actions of section IV.B do in fact affect the CS threshold in the desired way, to converge to a good setting that is a function of the receiver's SINR. The fading model used in most of the simulations is not a very good representation of small-scale fading in stationary networks (See below), but it seems like the proposed method would still be beneficial. > *** Detailed comments: Please provide detailed comments that will be helpful to the TPC for assessing the paper, as well as feedback to the authors. The fading model used in the simulation is not a very good representation of small-scale fading in stationary networks. It uses a Rician fading model for mobile transceivers for the case of stationary nodes with mobile objects in the channel. The two are not the same. When there are some objects moving in the channel, only a few multipath are affected. When a transceiver is moving, all multipath are affected. Thus in the case of static nodes and mobile objects in channel, the fading will not be as severe. Perhaps the Rician model would approximate the fading if a high Rician K factor is used. In fact, one simulation uses a higher K factor of 30 (Figure 11a,b), and shows that the method does still have a performance advantage, so this is not a severe criticism. However, when the criticism of [1-3] is based on its susceptibility to fading, a valid model should be used. Another criticism is on the comment on page 1, that power control is not addressed in this work, for one reason, because it introduces asymmetric links. Rate adaptation does as well; so this is not reason enough to neglect transmit power control. Finally, the figures are very hard to read on a paper - the font size is small and the plot lines use nearly identical line markers. ======= Review 2 ======= > *** Familiarity: Rate your familiarity with the topic of the paper. Novice (1) > *** Recommendation: Your overall rating. Strong Accept (5) > *** Contributions: What are the major issues addressed in the paper? Do you consider them important? (Pls. comment explicitly on the relevance of the paper to MASS topics, the technical depth and the importance of the problem addressed.) [Be brief] This paper addresses the problem of channel contention in wireless ad hoc networks. The objective of the work is to decrease interference, hence increase the SINR and maximize aggregate throughput. The idea is to increase spatial reuse by adjusting the carrier sense threshold and the transmission rate jointly together. This is referred to as dynamic spatial back-off. The novelty wrt previously proposed spatial back-off schemes is that this approach works even in the presence of small scale multipath fading, and it uses only local information (observed mean channel gain) and a single bit feedback in ACK packets from the receiver. > *** Strengths: What are the major reasons to accept the paper? [Be brief] Introduction explains the context, positions the work wrt existing approaches, and encourages the reader to read further. Description of the proposed algorithm is provided with sufficient level of details, explanations, and examples. Simulations are correctly described, and the results show superiority of the proposed algorithm wrt existing approaches. The structure of the paper is appropriate, English is good. The paper is easy to follow. > *** Weaknesses: What are the most important reasons NOT to accept the paper? [Be brief] I don't see any major reason for not accepting this paper. > *** Detailed comments: Please provide detailed comments that will be helpful to the TPC for assessing the paper, as well as feedback to the authors. This is a well written paper with a solid contribution. Some minor observations: In Figures 10 and 11, the lines corresponding to the proposed algorithm and to ODSB cannot be distinguished. The other curves are also hardly distinguishable (in other figures too). Quality of the figures in general should be improved. Some typos: "In contrast, the fewer concurrent transmissions, the higher SINR at the receivers, and consequently the higher transmission rate at which ..." --> In contrast, the fewer the concurrent transmissions, the higher the SINR at the receivers, and consequently the higher transmission rate at which ... "aim to adapt" --> aim at adapting ======= Review 3 ======= > *** Familiarity: Rate your familiarity with the topic of the paper. Expert (3) > *** Recommendation: Your overall rating. Strong Accept (5) > *** Contributions: What are the major issues addressed in the paper? Do you consider them important? (Pls. comment explicitly on the relevance of the paper to MASS topics, the technical depth and the importance of the problem addressed.) [Be brief] The paper depicts a novel extension of the spatial back off algorithm firstly proposed by X. Yang and N. H. Vaidya. The aim of the proposed modification is to solve the channel contention problem by adjusting both the carrier sensing threshold and the transmission rate dynamically. The channel contention issue is a major and a timely contribution making the paper relevant to the IEEE MASS topics. Moreover, the core contribution of the paper is very interesting and solid. > *** Strengths: What are the major reasons to accept the paper? [Be brief] The channel contention issue is a major and a timely contribution. Moreover, the paper is well written, well structured and presents a very interesting and solid core contribution. > *** Weaknesses: What are the most important reasons NOT to accept the paper? [Be brief] The performance results show very good results in term of throughput, in contrast with the classical scheme (without the proposed extension). However, a mathematical model should be more helpful and adequate to demonstrate such features. > *** Detailed comments: Please provide detailed comments that will be helpful to the TPC for assessing the paper, as well as feedback to the authors. The paper depicts a novel extension of the spatial back off algorithm firstly proposed by X. Yang and N. H. Vaidya. The aim of the proposed modification is to solve the channel contention problem by adjusting both the carrier sensing threshold and the transmission rate dynamically, which allows achieving higher throughput than the static schemes. The introductory section sets up very well the subject of the paper and heavily motivates readers. Moreover, the related work section presents the most important works addressing the channel contention issue. The core contribution of the paper is very interesting and solid. The experimental results show that the proposed extension allows achieving a higher aggregated throughput than the static schemeā~@~Ys maximum achievable throughput. -----------------------------------------------------------------------------