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.

Quadrature amplitude modulation transmission system

Abstract: The transmission system uses amplifier circuits with separate phase and amplitude control, the signals to be transmitted converted into digital signals with successive multi-stage symbols selected from a defined complex value symbol alphabet via the input signal. The real and imaginary components of the selected symbols are filtered for reducing their bandwidth and used for determining the phase and amplitude control of the amplifier circuits in the modulation end stage.

Optical fiber vibration sensor using (Pancharatnam) phase step interferometry

Abstract: A fiber-optic vibration sensor based on polarization and phase-step interferometry is reported. Left- and right-circularly polarized light coming back from the reference and signal arms of a modified Michelson fiber interferometer is processed with an array of five linear analyzers separated angular steps of /spl pi//4 (rad) from each other. Thus, five interference patterns are acquired simultaneously and the dynamical phase retrieval problem is reduced to five-step interferometry in the time-domain. A vibration sensor as described above was built by the authors and its performance was investigated.

Method and system for improving communication in a vehicle

Abstract: An embodiment and/or method to improve communication in a vehicle. Voice signals of the occupants of a vehicle may be picked up on an individual basis via separately arranged microphones. The individually picked-up voice signals may then be amplified separately for each occupant in an input stage and filtered for purposes of minimizing interference levels and for frequency adaptation. The signals may be subjected in a process stage to a signal processing that may be specific to each output channel, in the form of a delay correction and a level differentiation. And, via an adaptation stage having a level adaptation, the signals may then be distributed to likewise separately assigned loudspeakers, in accordance with the spatial conditions of the vehicle and the desired loudness level. The embodiment and/or method may be effectively used in passenger cars, larger vehicles including multimedia buses and trucks, ships, trains and airplanes/airborne spaces.

Process for operating a mobile radiotelephone system utilizing subscriber indentification modules

Abstract: In a process for operating a mobile radiotelephone system in which mobile stations are actuated with the aid of an identification number transmitted from the mobile station concerned to an active system in that, after the identification number has been checked in the active system in a data set which contains at least the identification number and a call number allocated thereto, a status field is set to "active", and in which, on the receipt of a request for connection with a call number the active system checks whether that call number is active, in which, if there is a match, a connection is made using the call number, the data set contains a reference to a further data set which contains a further identification number, a further call number, a further status field and a reference to the data set. When a request for connection to the call number is received, if the latter is not active, a connection is made using the further data set if it is active.

Gossip Based Streaming with Incentives for Peer Collaboration

Abstract: Peer-to-peer (P2P) systems are becoming a popular means of streaming audio and video content but they are prone to bandwidth starvation if selfish peers do not contribute bandwidth to other peers. We prove that an incentive mechanism can be created for a live streaming P2P protocol while preserving the asymptotic properties of randomized gossip based streaming without any incentives. In order to show the utility of our result, we adopt a distributed incentive scheme from P2P file storage literature to the live streaming scenario. We provide simulation results that confirm the ability to achieve a constant download rate (in time, per peer) that is needed for streaming applications on peers. The incentive scheme fairly differentiates peers' download rates according to how much useful bandwidth they contribute back to the P2P system, thus creating a powerful quality of service incentive for peers to contribute bandwidth to other peers. In addition we provide preliminary data from a real implementation of a gossip based streaming application