From: shenoy@cs.umass.edu Date: Wed, Nov 7, 2012 at 3:59 AM Subject: [COMSNETS] Acceptance of submission #19 "Token-DCF: An Opportunistic MAC protocol for Wireless Networks" To: "Hosseinabadi, Ghazale" Cc: Sergey Gorinsky   Dear Ghazale Hosseinabadi,   We are delighted to notify you that COMSNETS 2013 accepted your submission #19 "Token-DCF: An Opportunistic MAC protocol for Wireless Networks" for presentation at the conference and publication in the conference proceedings.   COMSNETS 2013 received 144 submissions. The rigorous review process included an initial screening for plagiarized or incorrectly formatted papers, reviewing of each remaining paper by at least 3 TPC members, on-line TPC discussions, and TPC telecon meeting on November 2nd. The TPC accepted a total of 38 papers, i.e., the acceptance rate is 26%. We sincerely congratulate you on the acceptance of your submission.   The reviews of your paper are enclosed and also available at the submission management site: http://comsnets13.cs.umass.edu/main/paper/19 .   December 2, 2012 is the firm deadline for submitting the camera-ready version and copyright form for your paper. Please start revising your paper based on the provided reviews. We will send you a link to the detailed camera-ready instructions shortly.   Note that COMSNETS 2013 will follow the IEEE ComSoc policy on registration requirements for authors of accepted papers: For the paper to appear in the proceedings, we require that at least one co-author of the paper be registered for the conference at the FULL IEEE or NON-MEMBER rate. In addition to the registration requirement, all papers MUST be presented at the conference. Papers that are not presented at the conference will not be recognized as a COMSNETS 2013 publication, will not appear in the final program, and will not be placed in the IEEE Digital Library (IEEE Xplore). Inadequate planning, including late applications for travel visas, will not be considered an acceptable basis for an exception to the presentation requirement.   We look forward to receiving the final version of your paper, and to seeing you in Bangalore, India in January 2013.   Congratulations again and best regards,   Srikrishna Bhashyam, Sergey Gorinsky, and Prashant Shenoy ===========================================================================                            COMSNETS Review #19A                  Updated Sunday 14 Oct 2012 1:59:40am EDT ---------------------------------------------------------------------------    Paper #19: Token-DCF: An Opportunistic MAC protocol for Wireless               Networks ---------------------------------------------------------------------------                       Overall merit: 3. Minor issues and reasonably                                         acceptable                  Reviewer expertise: 3. Knowledgeable                             Novelty: 3. Incremental improvement                           Relevance: 3. Moderately relevant                          ===== Paper summary ===== The paper proposes a variation to the 802.11 DCF that results in improved throughputs. The main idea is for the transmitting station to hand over a token to one of the listening nodes, which can then transmit after a SIFS. While there is no performance analysis, there are adequately many NS-2 simulations to drive home the advantage of the proposed modification.                       ===== Comments for author ===== The idea proposed in the paper is simple but effective. The paper is also well written and I think is acceptable. However, the paper is not without its drawbacks. 1. As pointed in the introduction, a number of researchers have tried to improve various aspects of DCF over the years. In such a well researched area, any new proposal should be compared directly with prior art and not just DCF. 2. While NS-2 simulations are great, I think analysis has its own value and may shed light on why and to what extent the tokens help. The paper makes no attempt in this direction. ===========================================================================                            COMSNETS Review #19B                 Updated Tuesday 23 Oct 2012 10:13:51am EDT ---------------------------------------------------------------------------    Paper #19: Token-DCF: An Opportunistic MAC protocol for Wireless               Networks ---------------------------------------------------------------------------                       Overall merit: 3. Minor issues and reasonably                                         acceptable                  Reviewer expertise: 3. Knowledgeable                             Novelty: 3. Incremental improvement                           Relevance: 2. Marginally relevant                          ===== Paper summary ===== The authors proposed a distributed and dinamically adaptive MAC protocol for wireless system, such as 802.11. This protocol has been suggested in order to reduce the idle time, which is the time a station has to wait in order to attempt the transmission over the channel, as well as the collision time, which happens when multiple stations transmit simultaneously. The protocol suggested is called Token-DCF because the novel idea is based on a token passing protocol: a transmitting station before transmitting, overhears the other active stations. According to queue lengths of its neighbours (with two different mechanisms, one focused on the fairness amongst the users while the other one focused on maximizing the efficiency of the system), decides which one of its neighbours can be eligible for the next transmission. Then a token for this specific neighbor is attached to the sent packet with a probability p < 1. In that way, the candidate station recognizes itself as next transmitter by overhearing the packet and getting the token. This station can transmit right after a period time equal to the SIFS (without waiting DIFS and backoff time) reducing the idle time and avoiding the collision, being the only transmitting station at that time. In the case where no token has been delivered, all stations wait for DIFS and backoff time to transm  it so that the protocol works as the original 802.11 DCF.                       ===== Comments for author ===== The selfishness of the users has not been considered: a pair of users can pass the token each other, getting always the priority in the transmission. A very dynamic scenario is needed in the performance evaluation because in the case of several joining, Token-DCF can work worse than original 802.11 DCF. This happens because the transmitting station cannot choose as candidate next station one of the new arriving stations, since they didn't make available yet the information about their queue. ===========================================================================                            COMSNETS Review #19C                  Updated Tuesday 30 Oct 2012 4:28:06am EDT ---------------------------------------------------------------------------    Paper #19: Token-DCF: An Opportunistic MAC protocol for Wireless               Networks ---------------------------------------------------------------------------                       Overall merit: 3. Minor issues and reasonably                                         acceptable                  Reviewer expertise: 3. Knowledgeable                             Novelty: 3. Incremental improvement                           Relevance: 2. Marginally relevant ===========================================================================                            COMSNETS Review #19D                 Updated Wednesday 31 Oct 2012 1:58:03pm EDT ---------------------------------------------------------------------------    Paper #19: Token-DCF: An Opportunistic MAC protocol for Wireless               Networks ---------------------------------------------------------------------------                       Overall merit: 4. Good choice for acceptance                  Reviewer expertise: 3. Knowledgeable                             Novelty: 4. New contribution                           Relevance: 4. Highly relevant                          ===== Paper summary ===== This paper describes Token-DCF, a distributed and adaptive variant of the 802.11 standard. A transmitting node selects a node from the set of its neighboring nodes for subsequent transmission. Such a privileged node is selected either randomly or by making use of queue length information. An algorithm that dynamically adapts the system parameters as well as selects the privileged node is given. The paper also  provides numerical results demonstrating the advantages of the distributed token DCF method.                       ===== Comments for author ===== The paper is well written, however it could have been made more crisp.  Certain details are a bit repetitive.  Also, explaining the results of some of the figures would add significant value to the paper. For example, in  Fig 5 we see that the number of idle slots for the Token-DCF system increases (marginally) with the number of nodes, while for 802.11 it appears to decrease; an explanation would have made for a better reading experience. Having said that, I have a major issue with the motivation for the paper. With smaller networks and increasing data rates, the source of inefficiency is probably more in the RTS-CTS handshake that precedes data transmission. Further, in these small networks the loss of efficiency due to collisions and corresponding idle times would be smaller and perhaps negligible compared to the loss of efficiency due to the slow RTS-CTS mechanism. This reviewer would have liked to see a discussion on the reduction (if any) inefficiency in the protocol before the data transfer (RTS-CTS for 802.11 and the token handoff for the proposed protocol).