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.

Credit card with implanted IC

Abstract: A credit card 2 with international standardisation of the external dimensions and the position of the contact areas of the implanted semiconductor chip 1 is constructed in such a manner that the semiconductor chip 1 is arranged on a removable plug-in part 3 which is significantly smaller in its dimensions compared with the credit card 2. This plug-in part, together with the credit card surrounding it, remains useable for the previous credit card applications. If it is pressed out of the credit card, it can be applied as independent minichip card in much smaller terminals (Figure 1).

An optical infrastructure for future telecommunications networks

Abstract: For the transport of the increasing traffic volume caused by existing and new narrowband services and evolving broadband services, the enhancement of the existing public telecommunication transport network is necessary. For this purpose an optical network layer with cross-connect and add/drop functionalities will be added to the existing transport network. A comparative analysis of space, time, and optical frequency division multiplexing has shown that for the time being optical frequency multiplexing is best suited for the realization of that new network layer. This multiplexing scheme offers the greatest advantages such as very high bandwidth utilization in the fiber and simple and efficient cross-connecting of high bitrate streams. In the near future, technology will be mature enough for the realization of a demonstrator network based on optical frequency division multiplexing. The functionalities of the optical network are evaluated and the results clearly show that optical frequency conversion and regeneration should be provided by the optical network. The article also deals with the realization aspects (cross-connecting, supervision, and operation and maintenance) of an optical node. >

Uplink performance of a multicarrier-CDMA mobile radio system concept

Abstract: Currently the air interface of future mobile radio systems is the topic of worldwide investigations. In this context CDMA (code division multiple access) seems to be a promising candidate as an element of the air interface of future mobile radio systems. The combination of OFDM (orthogonal frequency division multiplexing) and CDMA for mobile radio transmission has been proposed by several authors for the downlink. So far, the more elaborate uplink of such OFDM-CDMA mobile radio concepts has only been the topic of few publications, since channel estimation and data detection are more complex than in the downlink. The uplink of an OFDM-CDMA mobile radio concept is investigated. A pilot tone based channel estimation technique is proposed and several detection techniques suitable for the approach are described. Simulation results are shown for the case of a single receiver antenna as well as for dual receiver antenna diversity. The simulation results indicate that the proposed concept is well suited for future mobile radio systems.

Continuously chirped DFB gratings by specially bent waveguides for tunable lasers

Abstract: We have implemented and studied a new type of tunable multiple-section semiconductor distributed feedback (DFB) laser using tailored chirped DFB gratings. Arbitrarily and continuously chirped DFB gratings are defined by bent waveguides on homogeneous grating fields with ultrahigh spatial precision. The mathematical bending functions are optimized in this case to provide enlarged wavelength tuning ranges. We present the results of model calculations, the technological device realization and experimental results of the DFB laser characterization e.g. a tuning range of 5.5 nm without wavelength gaps and high side mode suppression ratio. >

Towards the delay sensitivity of games: There is more than genres

Abstract: Cloud gaming promises many advantages from the user and game developer perspective. But besides its benefits, cloud gaming suffers from two bottlenecks: bandwidth and latency. Although, many researchers have identified delay as an important factor on the QoE in gaming, the cause of varying tolerances towards delay in different games is not yet well understood. In this paper, we want to show that delay sensitivity should not be generalized for an entire game or genre. Instead, a specific scenario with its underlying characteristics should be considered, since differences within the same game can be higher than differences to another game. To investigate the delay sensitivity of games, we assessed quality features such as control, difficulty, delay perception, annoyance, and fairness for highly similar scenarios only differing in their pace or perspective. Results show that changing the pace within the same game can lead to stronger differences in respect to the delay sensitivity than using another game type. Furthermore, we explain how quality features might be used in the judgement process of a player and define a set of input action metrics for a future delay sensitivity based classification of games.