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CQR Best Paper Awards
| 2011, Naples, Florida, USA | 2010, Vancouver, Canada | 2009, Naples, Florida, USA | 2008, Carefree, Arizona, USA |
Announced in CQR 2011, May 10-12, Naples, Florida
Blazej Lewcio, Benjamin Belmudez, Amir Mehmood, Marcel WÄltermann and Sebastian MÖoller
"Video Quality in Next Generation Mobile Networks - Perception of Time-Varying Transmission"
Abstract - Next Generation Mobile Networks (NGMNs) provide an all-IP wireless platform for multimedia service delivery. The integrated communication system creates new perspectives for wireless video distribution and quality provisioning. Depending on the mobility patterns of the nomadic users, the link layer characteristics may rapidly change. Furthermore, mobility and service adaptation events like network handovers, video bitrate switching, or codec changeovers, may affect the user perception. Provisioning “always best connected” video services requires a thorough knowledge of video quality perception in NGMNs. In this paper, we address this problem. A subjective test including 50 NGMN conditions has been carried out. They were arranged in groups to assess the impact of 1) the access technology and network handover, 2) video codecs and codec changeover, 3) video bitrate and bitrate switching, and 4) to provide guidelines for packet loss adaptation. We could identify the perceptual bottlenecks of the future wireless communication and are able to propose perceptual guidelines for mobility management. In this way, this paper contributes to the service quality improvement of future wireless communications.
Yohei OKADA, Shingo ATA, Nobuyuki NAKAMURA, Yoshihiro NAKAHIRA and Ikuo OKA
"Application Identification from Encrypted Traffic based on Characteristic Changes by Encryption"
Abstract - Application identification is paid much attention by network operators to manage application based traffic control in the Internet. However, encryption is one of the factors to make application identification difficult, because it is so hard to infer the original (unencrypted) packets from encrypted packets. Therefore the accuracy of application identification is getting worse as the increase of encrypted traffic. In this paper, we propose a method to increase the accuracy of application identification whatever the traffic is encrypted or not. To achieve this we first investigate how the traffic characteristics have been changed by encryption. We then apply these results for more accurate application identification. Numerical results show that our method can improve the accuracy of identification for encrypted traffic up to 28.5 % compared to existing techniques.
Michael Todd GARDNER and Cory BEARD
"Evaluating Geographic Vulnerabilities in Networks"
Abstract - In wireless ad-hoc and wireline networks used for search and rescue, military operations, and emergency communications, many failure modes are geographic in nature. They include jammers, explosions, enemy attacks, terrain issues, and natural causes like floods, storms, and fires. This paper proposes two methods to gain valuable insights into the physical topography and geographic vulnerabilities of networks. The 2-Terminal method and All-Terminal method find areas that given a threat of a certain radius can disconnect either the source and destination pair or any component of the network respectively. We believe that these methods could be used to optimize network node selection, placement and design. To be tractable, both methods incorporate innovative search techniques to use the size of the threat to reduce the complexity of the search.
Announced in CQR 2010, June 8-10, Vancouver, Canada
Hiroshi YOSHIDA, Kosuke NOGAMI, and Kozo SATODA
"Proposal and Evaluation of Joint Rate Control for Stored Video Streaming"
Abstract - Rate control, which involves adapting the sending rate and video rate to network environments, is effective for stably streaming stored video over unmanaged IP networks. In this paper, we propose a novel rate control technique for optimizing the evaluation function defined as user-perceived video quality using an optimal control law in modern control theory. We call our method Joint Rate Control because it integrally controls both the sending rate and video rate. The results of numerical evaluation show that Joint Rate Control improved the evaluation function value by about 20%–50% from that of a conventional rate control method. We have demonstrated that Joint Rate Control optimizes the video quality; that is, this control method was the most effective in streaming video.
Announced in CQR 2009, May 10-12, Naples, Florida
Sanghyun CHI and Baxter F. WOMACK
"Predicting the Quality of Voice over IP Networks"
Abstract - Clients have still hesitated to switch conventional phone service with voice over IP networks (VoIP) service because VoIP service providers are not successful in providing consistent quality during a call. The uncertainness of IP networks, the legacy of packet-switched networks, makes it hard to predict service quality and demands real-time based monitoring. In this paper, we propose a prediction voice quality metric to monitor the quality of VoIP service. Based on a learning machine, the proposed metric nonlinearly weighs network parameters to estimate speech quality. Finally, performance analysis shows that the proposed metric achieves the high prediction accuracy.
Takamichi KIKKAWA, Takamichi MIYATA and Katsunori YAMAOKA
"Proof of optimal algorithm for maximum-bandwidth ALM tree construction"
Abstract - We construct an ALM tree that achieves the maximum bandwidth by using underlay topology information. Since this problem was previously shown to be NP-hard, no polynomial time algorithms for maximum-bandwidth ALM tree construction exist. In our work, we assume that the underlay network has a tree network topology, and we show a polynomial-time algorithm that constructs a maximum-bandwidth ALM tree on such a tree network topology. We propose an ALM tree construction algorithm that achieves bandwidth b and apply this algorithm with various bandwidth values b. We show that it can make a maximum-bandwidth ALM tree in polynomial time.
Announced in CQR 2008, April 29 - May 1, Carefree, Arizona
Hiromi UEDA, Toshinori TSUBOI, and Hiroyuki KASAI
"Hitless protection switching method for passive optical network"
Abstract - The Passive Optical Network (PON) shares transmission facilities to provide broadband services economically. To enhance network survivability, ITU-T Rec. G.983.5 defines some protection switching methods. These methods, however, always bring about signal loss when switching is performed. Moreover, a network operator often has to replace one optical fiber cable with another that takes a different route due to constructions like social infrastructure renewal. If hitless switching is available, the operator can carry out that activity anytime without impacting users, and can also offer higher-grade broadband services. Thus the hitless protection technology for PON systems is very attractive and useful. This paper proposes hitless switching methods for PON systems based on the PON’s unique features. We also present a specific hitless protection method for GE-PON as a design example.
Lee SPEAKMAN, Yasunori OWADA, and Kenichi MASE
"An analysis of loop formation in OLSRv2 in ad-hoc networks and limiting its negative impact"
Abstract - Transient routing loops have been observed to form in Ad-hoc Networks running the OLSRv2 routing protocol. The looping traffic significantly increases the impact on the surrounding network and its traffic thus degrading end-to-end transmission by a significant factor even though only a small proportion of the traffic may enter these loops and only for a brief time. This becomes significantly more evident when Link Layer Notification is used to catch broken links, inadvertently leading to the increase in loops. The ways in which these loops form and why Link Layer Notification significantly increases the number of loops is analyzed. Two methods of Loop Detection is introduced in this paper and used in combination with Packet Discard to selectively and preemptively discard those packets that are unlikely to reach their destination and are contributing to the load on the network. The effect of this Loop Suppression is to negate the detrimental effects on surrounding traffic and is found to improve network performance significantly.
Mizuho KODAMA, Go HASEGAWA, and Masayuki MURATA
"Implementation experiments of TCP Symbiosis: bio-inspired mechanisms for Internet congestion control"
Abstract - In this paper, we investigate the performance of a Linux implementation of a new congestion control mechanism for TCP, TCP Symbiosis. Whereas the traditional TCP Reno recognizes the network congestion only by detecting packet losses, TCP Symbiosis directly obtains the information of physical capacity and available bandwidth of the network path between sender and receiver hosts, and utilize an algorithm based on the mathematical models from biophysics to regulate the congestion window size. The proposed mechanism controls the sending rate by bandwidth information and therefore it can avoid self-induced packet losses on bottleneck links. We implement the proposed mechanism on Linux kernel system and investigate the performance through experiments using the public Internet environments in Tokyo and Osaka, Japan and USA. We show the effectiveness of the proposed mechanism, especially in terms of average throughput, stability, sensitivity to bandwidth change, and scalability to the bandwidth-delay product.
Last updated on Sunday, May 22, 2011