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.

Characterization of surface damage in dry-etched InP

Abstract: Sn-doped InP wafers were etched by reactive ion beam etching (RIBE) using a gas mixture of at ion energies varying from 100 to 600 eV We investigated the radiation damage caused by RIBE using various techniques which are sensitive to the near-surface region The optical and electrical properties of the damaged layer as a function of ion energy were studied by photoluminescence microscopy (PLM), photoluminescence spectroscopy, spectroscopic ellipsometry (SE) and electrochemical capacitance - voltage profiling The electron channelling pattern technique (ECP) was used to examine the structural disorder The observed radiation damage was attributed to the formation of phosphorus vacancies indicating preferential loss of phosphorus in the InP We found optimum etching conditions at an ion energy of 400 eV representing the best trade-off between high etch rate and low radiation damage The potential of PLM, SE and ECP as fast and non-destructive techniques for quality control in research as well as manufacturing is demonstrated

QoI-aware energy management for wireless sensor networks

Abstract: In this paper, we propose an efficient energy-management framework in wireless sensor networks (WSNs) to address the fundamental research challenge imposed by both the maintenance of the energy supply and the support of the quality-of-information (QoI) requirements. By quantifying the QoI benefit the tasks receive in relation to the level of QoI they request as the QoI satisfaction index), we propose a QoI-aware energy-management scheme to distributedly decide the participating state of each sensor. Specifically, by using the mathematical framework of the Gur Game, we propose a novel pay-off structure taking into account the QoI and the energy consumption. We finally evaluate the proposed scheme under an event occurrence detection scenario, where the proposed scheme successfully guarantees less than 7% QoI outage, saves 80% of the energy reserve if compared with the lower bound solution, and achieves the suboptimum with only 4% gap if compared with optimal solution.

TCP-ROME: A transport-layer parallel streaming protocol for real-time online multimedia environments

Abstract: Real-time multimedia streaming over the Internet is rapidly increasing with the popularity of user-created contents, Web 2.0 trends, and P2P (peer-to-peer) delivery support. While many homes today are broadband-enabled, the quality of experience (QoE) of a user is still limited due to frequent interruption of media playout. The vulnerability of TCP (transmission control protocol), the popular transport-layer protocol for streaming in practice, to the packet losses, retransmissions, and timeouts makes it hard to deliver a timely and persistent flow of packets for online multimedia contents. This paper presents TCP-real-time online multimedia environment (ROME), a novel transport-layer framework that allows the establishment and coordination of multiple many-to-one TCP connections. Between one client with multiple home addresses and multiple co-located or distributed servers, TCP-ROME increases the total throughput by aggregating the re- sources of multiple TCP connections. It also overcomes the band- width fluctuations of network bottlenecks by dynamically coordinating the streams of contents from multiple servers and by adapting the streaming rate of all connections to match the bandwidth requirement of the target video.

5G Connected and Automated Driving: Use Cases and Technologies in Cross-border Environments

Abstract: The vision of cooperative, connected and automated mobility (CCAM) along Europe can only be realized when harmonized solutions that support cross-border traffic exist. The possibility of providing CCAM services along different countries when vehicles traverse various national borders has a huge innovative business potential. However, the seamless provision of connectivity and the uninterrupted delivery of real-time services along borders also pose technical challenges which 5G technologies promise to solve. The situation is particularly challenging given the multi-country, multi-operator, multi-telco-vendor, multi-car-manufacturer, and cross-generation scenario of any cross-border layout. Motivated by this, the 5GCroCo project, with a total budget of 17 million Euro and partially funded by the European Commission, aims at validating 5G technologies in the Metz-Merzig-Luxembourg cross-border corridor, traversing the borders between France, Germany and Luxembourg. 5GCroCo validation will focus on three use cases: 1) tele-operated driving, 2) high definition map generation and distribution for automated vehicles, and 3) Anticipated Cooperative Collision Avoidance. The results will help reduce the uncertainties associated with eV2X communications across borders in Europe in preparation of commercial 5G deployment.