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 & Terminal (electronics). The organization has 3473 authors who have published 5208 publications receiving 65429 citations. The organization is also known as: DTAG & German Telecom.

Mobile telephone with distance, angle or speed measuring functions has evaluation unit for measuring propagation time of received laser beam and calculates associated distance

Abstract: In addition to the modules required for telecommunication, the mobile telephone includes a laser transmitter-receiver with a laser source, and a lens for focussing the emitted radiation. Measurement data from an evaluation unit are supplied to a unit for transmitting the data via a mobile radio network (12) to a remote station, e.g. a personal computer (10). The evaluation unit measures the propagation time of a received laser beam (7), and calculates the associated distance.

Sybot: an adaptive and mobile spectrum survey system for wifi networks

Abstract: Information on site-specific spectrum characteristics is essential to evaluate and improve the performance of wireless networks. However, it is usually very costly to obtain accurate spectrum-condition information in heterogeneous wireless environments. This paper presents a novel spectrum-survey system, called Sybot (Spectrum survey robot), that guides network engineers to efficiently monitor the spectrum condition (e.g., RSS) of WiFi networks. Sybot effectively controls mobility and employs three disparate monitoring techniques - complete, selective, and diagnostic - that help produce and maintain an accurate spectrum-condition map for challenging indoor WiFi networks. By adaptively triggering the most suitable of the three techniques, Sybot captures spatio-temporal changes in spectrum condition. Moreover, based on the monitoring results, Sybot automatically determines several key survey parameters, such as site-specific measurement time and space granularities. Sybot has been prototyped with a commodity IEEE 802.11 router and Linux OS, and experimentally evaluated, demonstrating its ability to generate accurate spectrum-condition maps while reducing the measurement effort (space, time) by more than 56%.

Automation of facility management processes using machine-to-machine technologies

Abstract: The emergence of machine-to-machine (M2M) technologies as a business opportunity is based on the observation that there are many more machines and objects in the world than people and that an everyday object has more value when it is networked. In this paper, we describe an M2M middleware that we have developed for a facility management application. Facility management is a time and labour-intensive service industry, which can greatly benefit from the use of M2M technologies for automating business processes. The need to manage diverse facilities motivates several requirements, such as predictive maintenance, inventory management, access control, location tracking, and remote monitoring, for which an M2M solution would be useful. Our middleware includes software modules for interfacing with intelligent devices that are deployed in customer facilities to sense real-world conditions and control physical devices; communication modules for relaying data from the devices in the customer premises to a centralized data center; and service modules that analyze the data and trigger business events. We also present performance results of our middleware using our testbed and show that our middleware is capable of scalably and reliably handling concurrent events generated by different types of M2M devices, such as RFID tags, Zigbee sensors, and location tracking tags.

Conversation Analysis of Multi-Party Conferencing and Its Relation to Perceived Quality

Abstract: This paper investigates interactivity in multi-party conferencing. To this aim the state model often used to descibe two-party telephone conversations is redefined for more than two interlocutors. We adapt and apply statistical measures such as conversation state probabilities to recordings made during a three-party conferencing quality test, which was designed to evaluate the perceived quality under various speech transmission properties. In a second step, we associate the different observed degrees of interactivity to the quality test ratings. Results give a first insight into the co-dependence of transmission properties, the interlocutors' communication behavior and their integral quality judgment.

An optimal distributed malware defense system for mobile networks with heterogeneous devices

Abstract: As malware attacks become more frequent in mobile networks, deploying an efficient defense system to protect against infection and to help the infected nodes to recover is important to contain serious spreading and outbreaks. The technical challenges are that mobile devices are heterogeneous in terms of operating systems, and the malware can infect the targeted system in any opportunistic fashion via local and global connectivity, while the to-be-deployed defense system on the other hand would be usually resource limited. In this paper, we investigate the problem of optimal distribution of content-based signatures of malware to minimize the number of infected nodes, which can help to detect the corresponding malware and to disable further propagation. We model the defense system with realistic assumptions addressing all the above challenges, which have not been addressed in previous analytical work. Based on the proposed framework of optimizing the system welfare utility through the signature allocation, we provide an encounter-based distributed algorithm based on Metropolis sampler. Through extensive simulations with both synthetic and real mobility traces, we show that the distributed algorithm achieves the optimal solution, and performs efficiently in realistic environments.