Deutsche Telekom

About: Deutsche Telekom is a company organization based out in Welwyn Garden City, United Kingdom. It is known for research contribution in the topics: Telecommunications network & Signal. The organization has 3473 authors who have published 5208 publications receiving 65429 citations. The organization is also known as: DTAG & German Telecom.

PON measurements and monitoring solutions for FTTH networks during deployment and operation

Abstract: Optical fibre step by step substitutes existing copper cable infrastructure in the carriers' access networks, enabling new broadband services. One common approach, a passive optical network (PON) infrastructure, basically consists of optical fibres and splitters, which are lit up by G-PON (Gigabit/s-PON) or XG-PON (10 Gigabit/s-PON). These systems are attenuation limited, therefore the loss budget of a PON is of high importance. For the deployment process the total attenuation of the PON, between Central Office (CO, OLT) and customer site (ONT), must be accurately monitored and kept below the values specified in G.984.x and G.987.x standards. In FTTH scenarios the PON attenuation measurements must include the in-house networks up to the subscriber fibre cable termination unit.

Contact duration aware evaluation for content dissemination delay in mobile social network

Abstract: Groups of people with mobile phones using short-range connections such as WiFi and Bluetooth to propagate messages can be modeled as, with regard to regular absence of end-to-end connection, mobile social networks MSNs, which can be exploited to offload a significant amount of mobile content from the overloaded infrastructure networks such as 3G. The study of content transmission delay for the applications of mobile content dissemination in MSNs is an important problem, because to enhance the network capacity, the traffic is offloaded at the cost of inducing longer delay. In contrast to existing works, which ignore the factors of contact duration limits and large content size, we present a contact duration aware framework to model the content dissemination process in MSNs, give an explicit expression for the average content dissemination delay, and reveals its relationship with various system parameters of content size, users' selfishness, number of involved subscribers, infecting ratio, and so on. We apply our proposed model to real-life traces to assess its reliability by comparing the theoretical results with measured statistics and present extensive upshots to evaluate the influence of various parameters on system performance. The results demonstrate the accuracy of our proposed framework and reveal that system parameters of content size, system infecting ratio and intragroup transmission are the most important factors to influence the content dissemination delay. Copyright © 2013 John Wiley & Sons, Ltd.

Synchronization of a stereoscopic camera

Abstract: A method for synchronizing the recordings of two video cameras which are operated in parallel for the three-dimensional representation of an image sequence, in particular, of two digitally recording video recorders, a light signal being faded into the image area of the two cameras and simultaneously recorded by both cameras; and the playback of the recordings being synchronized using the recorded signals.

SmartTransfer: transferring your mobile multimedia contents at the "right" time

Abstract: Today's mobile Internet is heavily overloaded by the increasing demand and capability of mobile devices, in particular, multimedia traffic However, not all traffic is created equal, and a large portion of multimedia contents on the mobile Internet is delay tolerant We study the problem of capitalizing the content transfer opportunities under better network conditions via postponing the transfers without violating the user-specified deadlines We propose a new framework called SmartTransfer, which offers a unified content transfer interface to mobile applications We also develop two scheduling algorithms to opportunistically schedule the content transfers Via extensive trace-driven simulations, we show that our algorithms outperform a baseline scheduling algorithm by far: up to 17 times improvement in upload throughput and/or at most 20 dBm boost in signal strength The simulation results also reveal various tradeoff between the two proposed scheduling algorithms We have implemented our framework and one of the scheduling algorithms on Android, to demonstrate their practicality and efficiency

Mobile TCP usage characteristics and the feasibility of network migration without infrastructure support

Abstract: In this poster we describe initial findings regarding Internet usage characteristics, in particular TCP flows from a field study with 27 iPhone 3GS users. We present details regarding their usage characteristics, and provide a solution for migrating flows between different networks and/or network interfaces without requiring infrastructure support or changes to current applications and protocols, with minimal impact to the user.