======= Review 1 ======= > *** Contributions: What are the major issues addressed in the paper? Do you consider them important? Comment on the novelty, creativity, impact, and technical depth in the paper. supporting transmission of packets of different sizes via channel partition. > *** Strengths: What are the major reasons to accept the paper? [Be brief.] utilizing the flexibility of channel partition to solve a practical problem. > *** Weaknesses: What are the major reasons NOT to accept the paper? [Be brief.] the design is driven by simple heuristics, and the improvement is small. > *** Detailed Comments: Please provide detailed comments that will help the TPC assess the paper and help provide feedback to the authors. The authors tackle the problem of mismatch between packet size and channel spectrum by partitioning a single channel into a wideband and a narrowband channel. The narrowband channel is used to carry small-size packets while the wide-band channel is used for other packets. Using multiple radios, both channels can operate simultaneously. The main design challenge is for an AP to determine the appropriate partition to minimize waste in spectrum usage, while considering the traffic from its subscribers. While the partition algorithm is the key contribution of the paper, the authors spend little time in describing the design insights and details. The pseudo code contains several items that are difficult to understand: for example, rounding by 5, why 5 as the magic number here? The performance of the partition algorithm also depends heavily on the traffic demands, which should be evaluated. The authors should consider available traffic traces rather than using self-generated traffic patterns. > *** Recommendation: Your overall rating (Please try giving as few borderlines as possible). weak accept: top 30% of all submissions, but not top 20% (3) ======= Review 2 ======= > *** Contributions: What are the major issues addressed in the paper? Do you consider them important? Comment on the novelty, creativity, impact, and technical depth in the paper. The paper investigates how partitioning bandwidth may overcome the inefficiencies associated with transmission of short packets in 802.11. > *** Strengths: What are the major reasons to accept the paper? [Be brief.] The paper evaluates the benefits of partitioning the bandwidth of 802.11 on the total throughput in infrastructure WLANs. > *** Weaknesses: What are the major reasons NOT to accept the paper? [Be brief.] The idea and evaluation in the paper are simple and require changes to existing standards and implementation of these in new hardware (moreover requiring multiple radios in each MS and AP. It begs the question, why don't we shift the small packets to a reservation based window in time (modifications to PCF in WLANs) rather than breaking things in frequency. How will the approaches compare since we are breaking the bandwidth in time rather than frequency? > *** Detailed Comments: Please provide detailed comments that will help the TPC assess the paper and help provide feedback to the authors. The paper titled "WiSP: A Protocol for Overcoming MAC Overheads Using Packet Size Dependent Channel Widths" looks at partitioning the bandwidth of 802.11 to allow the inefficiencies associated with transmissions of small packets (e.g. 100 bytes) to be reduced. The approach, called WiSP is employed at an AP which determines how the bandwidth must be partitioned best depending on the flows that it sees. Evaluations are done using simulations. Fixed partitioning is shown to perform as well as WiSP due to the latency in partitioning of WiSP. There are several changes required to existing 802.11 standards (motivated by [5] cited in the paper) and in general to how things work (e.g., changing the transmit power of each channel). Evaluations are done at a fixed rate. By partitioning the channel, it is likely that the channels will see different qualities. What happens if the lower bandwidth channel can transmit at higher rates (say 64-QAM with 3/4 coding) compared to the higher bandwidth channel (only QPSK)? The results also include no confidence levels - how many times were the simulations run? Are the numbers shown time averages? Are flows for different clients impacted differently? Please also see weaknesses. > *** Recommendation: Your overall rating (Please try giving as few borderlines as possible). weak reject: top 50% of all submissions, but not top 30% (2) ======= Review 3 ======= > *** Contributions: What are the major issues addressed in the paper? Do you consider them important? Comment on the novelty, creativity, impact, and technical depth in the paper. Te paper elaborates a self adaptive channel splitting protocol which works well in cases in which large packets and small packets are send within a wireless network. The appraoch is evaluated thoroghly by simulations. > *** Strengths: What are the major reasons to accept the paper? [Be brief.] The idea of allocating a speific channel (part of existing channels) for small packets seems to help improving throughput. The appraoch is evaluated thoroghly by simulations. The authors explain limitations of their approach as well. > *** Weaknesses: What are the major reasons NOT to accept the paper? [Be brief.] I feel a bit unsure aboutfit to the conference, i.e. the evaluated approach is 802.11 mobiles and a fixed access point which might be considered as mesh.... The approach requires AP and mobile devices hardware to be extended with a second transceiver at least, so it is of low importance for short term real world scenarios, but this might be a very minor point for scientific conference evaluation. > *** Detailed Comments: Please provide detailed comments that will help the TPC assess the paper and help provide feedback to the authors. The paper is well written, the idea is clearly described and evaluated, so this is one of the few papers which can go as is. > *** Recommendation: Your overall rating (Please try giving as few borderlines as possible). accept: top 20% of all submissions, but not top 10% (4) ======= Review 4 ======= > *** Contributions: What are the major issues addressed in the paper? Do you consider them important? Comment on the novelty, creativity, impact, and technical depth in the paper. The paper proposes a scheme to improve throughput efficiency of IEEE 802.11-based WLANs. The rationale of the proposed scheme is to assign narrower frequency channels to the transmissions of shorter packets, while dedicating broader channels to long ones. The proposed scheme is centrally implemented at an access point. Simulations are used to validate the proposed ideas which are also compared to the dual strategy of frame aggregation in larger channels. > *** Strengths: What are the major reasons to accept the paper? [Be brief.] The paper is nicely written and motivated. The proposed idea is interesting and well explained. The simulation analysis is convincing. > *** Weaknesses: What are the major reasons NOT to accept the paper? [Be brief.] The practical applicability of the proposed solution is really hard. Comments on fairness of the proposed scheme would be required. > *** Detailed Comments: Please provide detailed comments that will help the TPC assess the paper and help provide feedback to the authors. The paper is nicely written. The proposed idea is novel (to my knowledge), clearly explained and motivated. All in all, I believe that the manuscript provides a nice contribution and is further provocative in proposing a shift in the usual ways to improve throughput of WLANs. The main drawback of the proposed scheme is applicability. In fact, the core idea requires transmitters and receivers which are able to switch the operating channel (and channel width) on a per-packet basis, which may pose hard constraints on the PHY. A broader discussion with this respect would be useful. Another concern I have deals with fairness of the proposed scheme, which inherently assigns lower-rate “channels” to short-packet traffic. What is currently missing in the performance evaluation section is a thorough analysis of the fairness issue. As an example, VoIP clients of the WLAN (with short packets in average) may be systematically offloaded to narrow channels. I would suggest the authors to report per-user fairness measures. Finally, since the inspiring work for the present one is reference [5], I would suggest the authors to dedicate more time and text in describing the contributions of [5]. > *** Recommendation: Your overall rating (Please try giving as few borderlines as possible). accept: top 20% of all submissions, but not top 10% (4)