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.

PMD compensation in 10 Gbit/s NRZ field experiment using polarimetric error signal

Abstract: A technique for compensating for the polarisation mode dispersion of a 10 Gbit/s non-return to zero (NRZ) installed fibre link (45 km, 80 ps mean differential group delay), using a variable polarisation delay line and a set of polarisation controllers is presented. The variation of the output polarisation with frequency over the signal bandwidth was monitored using a frequency-resolving Stokes-polarimeter. A control loop is used to minimise the RMS deviation of the polarisation state at the receiver.

Method and device for producing a choice of either single photons or pairs of photons in an optical channel

Abstract: The invention relates to a method for producing a choice of either single photons or pairs of photons in an optical channel (16, 17), comprising the following steps: establishing a two-photon state (photon pair); physically separating said photon pair and obtaining the quantum mechanical correlation in the event that the photons are emitted collinearly; coupling each photon into one optical channel (14, 14', 14') respectively, one channel (15, 15', 15') containing an interferometer (7-13) with a variable difference in optical paths δ1F-δ1S and the other channel containing an optical retardation route (19) of optical length δ1; physically bringing the two channels together with a beam splitter (18, 31-36); matching the values δ1F, δ1S and δ1 in such a way that the probability K of coincidences between the outputs (16, 17) of the beam splitter can be either approximately K=0 or approximately K=1 or approximately a predetermined intermediate value, K=0 corresponding to a photon pair in one of the output channels (16, 17) of the beam splitter and K=1 corresponding to two single photons in the two output channels of the beam splitter. The invention provides a means of producing an optical separating filter or gate for either single photons or photon pairs which can be used in quantum cryptography and as a basic element of a quantum optical calculating machine.

Method and communication system for optimizing the throughput of a TCP flow in a wireless network

Abstract: A method and a system is provided for optimizing the throughput of a TCP flow from a TCP source to a TCP destination in a wireless network with the path of the flow encompassing a wireless link between a wireless transmitter and a wireless receiver. The throughput is optimized by using link-layer mechanisms at the wireless transmitter which are adaptive to the instantaneous TCP dynamics of the TCP flow. In particular, a cross-layer approach is disclosed which serves to tunnel information of TCP congestion control dynamics directly from the TCP based transport layer to the data link-layer which selects in response to these information modulation and/or coding schemas to transmit TCP segments via data link-layer blocks with improved TCP throughput.

Method and device for the remote operation and remote control of systems and apparatus via a telephone network

Abstract: The invention concerns a method wherein the establishment of connections between the base station and the adapters is made dependent on a unilateral authentication process. Before making his DTMF (dual tone multi-frequency dialling) selection, the user identifies himself with respect to the base station using coded data which comprise a 'key' and a 'secret' and are tested there for conformity with stored data concerning authorized persons. If conformity exists, readiness for connection to an adapter is acknowledged by means of a first ready signal. It is only then that, in a similarly coded manner, the adapter and type of actuation, which are acknowledged by status signals or a further ready signal, are selected. The method even enables critical functions with greater demands as concerns security to be remotely controlled via the public telephone network, for which dedicated lines would otherwise be necessary.

Emotion detection in dialog systems: Applications, strategies and challenges

Abstract: Emotion plays an important role in human communication and therefore also human machine dialog systems can benefit from affective processing. We present in this paper an overview of our work from the past few years and discuss general considerations, potential applications and experiments that we did with the emotional classification of human machine dialogs. Anger in voice portals as well as problematic dialog situations can be detected to some degree, but the noise in real life data and the issue of unambiguous emotion definition are still challenging. Also, a dialog system reacting emotionally might raise expectations with respect to its intellectual abilities that it can not fulfill.