CQR 2011, May 10-12, Naples, Florida
“Video Quality in Next Generation Mobile Networks – Perception of Time-Varying Transmission”
Blazej Lewcio, Benjamin Belmudez, Amir Mehmood, Marcel WÄltermann and Sebastian MÖoller
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.
“Application Identification from Encrypted Traffic based on Characteristic Changes by Encryption”
Yohei OKADA, Shingo ATA, Nobuyuki NAKAMURA, Yoshihiro NAKAHIRA and Ikuo OKA
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.
“Evaluating Geographic Vulnerabilities in Networks”
Michael Todd GARDNER and Cory BEARD
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.