Showing papers by "Deutsche Telekom published in 2002"

Decoding method and decoding device for a CDMA transmission system for demodulating a received signal available in serial code concatenation

Abstract: A method and a device for decoding for use in a code-division multiple access (CDMA) transmission system for demodulating a received signal available in serial code concatenation, with a two-step coding being carried out at the transmitting end of the transmission system, including an orthogonal, multi-step inner Hadamard code and an outer, error-correcting code of a predefined rate. In the receiver, a soft-in/soft-out decoder is provided, at whose input and output soft values are processed as reliability information, i.e., L-values. The soft output of the first decoder step, or inner code is the soft input for the decoder step, or outer code, that follows in each case, the first decoder step receiving the output values of the preceding demodulation, which contain the channel's reliability information. A soft output is used by the decoder, in particular a MAP decoder, as a-priori information for the systematic bits of the Walsh function of the inner code for decoding of the inner code.

On the systematic measurement errors of correlative mobile radio channel sounders

Abstract: We show that measurements of time-varying mobile radio channels obtained with uncalibrated correlative channel sounders are affected by four different types of systematic errors (commutation, pulse-compression, aliasing, and misinterpretation error). We analyze these errors and provide upper error bounds that are formulated in terms of channel and sounder parameters. Based on these error bounds, we provide guidelines for a judicious choice of important sounder parameters. Computer simulations using a simple two-path channel illustrate our theoretical results. Finally, we show how our results can be used to assess the accuracy of measured channel data.

Method for providing at least one personalized web user page

Abstract: Zu Beginn einer Internet-Sitzung erzeugt ein auf dem Personal Computer (70) eines Benutzers implementierter Browser die vom Provider erstellte Startseite. Die Startseite ist mehr oder weniger vom Provider voreingestellt und berucksichtigt das Zugriffsverhalten des Benutzers wahrend einer Internet-Sitzung nicht. Der Erfindung liegt daher die Aufgabe zugrunde, ein Verfahren sowie einen Computer-lesbaren Datentrager mit einem darauf gespeicherten Computerprogramm bereitzustellen, welches personalisierte Web-Benutzerseiten erzeugen kann. Hierzu wird zunachst zu Beginn einer Internet-Sitzung eine Web-Startseite auf das Web-taugliche Endgerat (70) geladen. Der Benutzer gibt anschliesend wenigstens einen Suchbegriff und/oder eine bestimmte Zieladresse zu einer bestimmten Webseite ein. Wurde ein Suchbegriff eingegeben, so werden zu diesem die entsprechenden Zieladressen erzeugt. Alle Zieladressen werden nachher in einem Benutzer-bezogenen Speicher (100, 120, 130) abgelegt. Anschliesend wird wenigstens eine personalisierte Web-Benutzerseite aus den gespeicherten Zieladressen, die in Abhangigkeit von wenigstens einem vorbestimmten Kriterium ausgewahlt werden, erstellt. Diese personalisierte Web-Benutzerseite wird Benutzer-gesteuert oder automatisch an dessen Endgerat dargestellt. Nach Beendigung der Sitzung wird die aktuelle personalisierte Web-Benutzerseite in dem oder einem anderen Benutzer-bezogenen Speicher (130) zur Weiterverwendung abgelegt.

UML-based performance engineering possibilities and techniques

Abstract: An information system's performance in relation to time and resources is largely determined by the design selected in software development. Performance engineering's core concept accounts for a software system's performance from the earliest development phases. Unfortunately, these measures are not performed explicitly during software development, primarily because of deadline pressure, the information system's complexity, or lack of knowledge of what PE means. The authors overview UML-based PE, analyze corresponding approaches, and examine the advantages of the tools available.

Method for customized data output on a web site

Abstract: The invention concerns a method for customized data output on a web site, whereby specific data can be added to the content of a web site in targeted manner for an Internet user or a specific group of persons. The invention aims at enabling customization up to the level of the individual Internet user. Therefor, a list of preferences is filed for the user in a databank of his Internet service provider (ISP), for example under his client number. When the user calls a web site, the web server contacted by the user requests said preferences from the ISP. Said server transmits to the databank server, on querying the databank, the temporary IP address from which the web site has been called. The databank server accesses through an inverse RADIUS request the user's preferences and transmits them to the web server which uses said preferences to add to the called web site the customized data corresponding to said preferences.

Influence of an ultrafast transient refractive-index grating on nonlinear optical phenomena

Abstract: With two interfering femtosecond pulses it is possible to produce an ultrafast transient refractive-index grating with relatively high contrast in a transparent material. The grating has a significant impact on nonlinear optical effects, it is responsible for a loss of surface sensitivity in second-harmonic generation from centrosymmetric materials, an enhancement of the generated third harmonic due to self-phase matching, and for the diffraction of the generated harmonics. The latter phenomenon is determined by the nonlinear equivalent of the diffraction law. In a nonresonant material, the refractive-index grating is a thin slide with the thickness of the spatial equivalent of the pulse duration, propagating through the crystal with the group velocity. The duration of the grating depends only on the pulse width, in our case 80\char21{}100 fs. Besides offering a fundamental point of view, this opens the way to a variety of interesting applications, in particular in telecommunications, such as any kind of beam manipulation, optical switching, or demultiplexing, all of them on a femtosecond time scale.

Method for reducing the out-of-band emission in AM transmitters for digital transmission

Abstract: The problem associated with digital transmission using existing AM transmitters is that the out-of-band emission that occurs must be reduced in order to comply with the ITU mask, as the shoulder distances that can be achieved by the AM transmitters are not sufficient for a satisfactory compensation. The signals that are required to control the AM transmitters, (amplitude signal and phase-modulated RF signal), are formed from the digital modulation signal by a Cartesian → polar transformation, whereby the bandwidth for the amplitude signal and RF signal reaches a value, which causes an unacceptable out-of-band emission. To prevent this, the invention provides methods for digital modulation, which avoid the zero point by a wide margin in their vector diagram representations, i.e. which form a 'hole' around the 0/0 point. Modulation methods of this type are referred to as offset modulations and coded modulations. A variant of 16APSK is particularly suitable, as a higher net data throughput can be achieved with only 16 set points and negligible error protection coding is required. To transmit an OFDM signal, the 'hole' in the vector diagram is obtained by offsetting the zero crossings for the I(t) and Q(t) signals and the latter is achieved by the insertion of a pulse into the subsequent component, e.g. I(t), if the other component Q(t) already falls short of a defined threshold value. A BPSK test sequence for measuring the radio channel can be used by means a modification, in which a modulation signal is formed by inserting a pulse between two pulses with a change of sign bit, said modulation signal having a 'hole' around the 0/0 point. The size of the hole can be adjusted by the inserted pulse.

Mobile phone, PDA, etc. incorporating medical sensors for determination of blood pressure, temperature, pulse, etc. so that the data can be automatically evaluated and compared with user data and if necessary a doctor informed

Abstract: Method for measurement and determination of medical information using a communications device with appropriate sensors, miniature computer, software and encryption software. Within the biometer communications device (1) sensors (3) are used to measure signals corresponding to medical values such as blood pressure, temperature, or pulse rate. The signals are processed and the values calculated for appropriate use. The measured values are compared with stored values and if necessary a stored address can be displayed and a doctor, medical center, etc. automatically informed.

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.

Method and arrangement for digital transmission using AM transmitters

Abstract: A method for digital transmission using an AM transmitter includes operating an output stage of the AM transmitter in a linear mode and correcting the supply voltage of the output stage in the linear mode as a function of an instantaneous drive so as to improve efficiency. The correcting is performed by operating the modulator of the AM transmitter as a switched-mode power supply unit so as to deliver a corrected supply voltage to the output stage, and scanning an envelope of a complex modulated data signal so as to control the correcting. A time constant during the scanning of the envelope enables immediate following of a rise in the envelope. The complex modulated data signal is delayed after the scanning so as to perform the correcting during the delay and prevent an overdriving of the output stage.

Representing visual information in telecommunications device involves projecting visual information into user's field of view with separate portable display device

Abstract: The method involves projecting the visual information into the user's field of view with a portable display device (16) that is separate from the telecommunications device (14) and that remains within his field of view. A display device in the form of a pair of spectacles or a helmet worn by the user can be used. Independent claims are also included for the following: a telecommunications device, especially for implementing the method.

Navigation system for partially-sighted person uses miniature video camera on pair of spectacles and camera on mobile telephone sending signals to navigation server at cell station

Abstract: The mobile telephone (2) has BT (Bit Transmission) and SMS (Storage Management Subsystem) functions or MMS (Medium Management Subsystem) functionality and incorporates a miniature TV camera. A further camera with BT may be mounted in a pair of spectacles (1) and transmits picture signals to the mobile telephone. The mobile telephone transmits picture signals to a cell station incorporating a position and navigation server (3). This is connected to a picture data bank (4) to enable the picture from the camera to be recognized.

Method for determining intensity parameters of background noise in speech pauses of voice signals

Abstract: Known methods for determining intensity parameters are based on the evaluation of short signal segments and their direct allocation to speech pauses or speech activity In order to distinguish speech from speech pauses, intensity thresholds are often used When the undisturbed source signal is used to mark speech pauses, a variably occurring time lag between source voice signal and disturbed voice signal often impedes exact transfer of the marking Intensity parameters of background noises in speech pauses can be determined from the frequency distribution of the intensity values for short signal segments using the method disclosed in the invention In order to assign intensity values, the fraction of speech pauses in the entire signal is calculated from the undisturbed source signal and defined as frequency threshold Intensity values below the frequency threshold are assigned to the speech pauses The arithmetic mean value of said intensity value is determined as intensity parameter for the background noise in the speech pauses Percentile parameters for background noises in speech pauses can also be calculated with the inventive method

Femtosecond third-harmonic generation:. self-phase matching through a transient. Kerr grating and the way to ultrafast computing

Abstract: The third harmonic of 810-nm 100-fs pulses at 130 μJ is generated very efficiently when ultrashort pulses from two noncollinear beams interfere in an optical medium to create an instantaneous transient grating via the optical Kerr effect. The grating couples two pathways for third-harmonic generation, each taking two photons from one beam and one photon from the other beam, respectively. The coupling enables self-phase matching in the complete process, resulting in a conversion efficiency of ≈3%. Scattering an independent beam at the transient grating confirms a lifetime limited by the pulse duration, with a reaction on the order of one optical cycle. Using the second harmonic of a Ti-sapphire laser at 405 nm, it is shown that the generation of the transient Kerr grating is a general feature, requiring less than 20 μJ/pulse. By introducing a third femtosecond beam we are able to emulate various digital logic units with femtosecond response.

Irregular terrain wave propagation by a Fourier split‐step wide‐angle parabolic wave equation technique for linearly bridged knife‐edges

Abstract: [1] A novel Fourier split-step algorithm for the solution of the parabolic wave equation is proposed. The derivations are based on a two-dimensional linearly bridged knife-edge terrain model that considers ideally conducting as well as dielectric lossy ground together with a dielectric lossy layer as macroscopic representation of vegetation and buildings. The boundary condition at the terrain interface is formulated in the spectral domain, and it is shown that waves with a very wide angular spectrum with respect to the horizontal can accurately be modeled as long as the dominant portion of energy propagates above the terrain. Validation results are given for an ideally conducting as well as lossy dielectric wedge and an ideally conducting rounded obstacle. Also, real-world propagation curves show good agreement with measured data.

Evaluation of novel resilience schemes in dynamic optical transport networks

Abstract: Today, Wavelength Division Multiplexing (WDM) transmission systems are deployed extensively in transport networks. They are used mainly for static point-to-point connections. With the availability of fast reconfigurable Optical Cross Connects (OXC) and the introduction of a control plane in the Optical Transport Network (OTN), optical channel based logical networks can be built for dynamic WDM networks. Resilience in current transport networks is mainly based on static SONET/SDH dedicated and shared protection. Distributed control planes allow new, flexible protection mechanisms (e.g. GMPLS reroute and fast reroute). To evaluate future distributed control concepts and new resilience schemes in transport networks, we have implemented a dynamic OTN simulation model. Several case studies have been performed using different protection and restoration methods. Different failure scenarios (single or multiple link failures) were used. The paper evaluates the case studies in terms of scalability, recovery time criteria, capacity use (efficiency) and availability. It is shown that the new and flexible resilience schemes are a promising alternative to traditional statically preplanned protection in transport networks. Furthermore, they provide increased network availability in multiple failure cases.

Verfahren und vorrichtung zur kundenseitigen personalisierung von gsm-chips

Abstract: The invention relates to a method for personalization of GSM chips. At least one subscriber identification character(IMSI) and a card number (ICCID) are stored in the memory area of said chips in addition to a secret key (Ki) and other optional data for personalization purposes. The invention aims to eliminate an unnecessarily high degree of complexity linked to management of all card data in an authentication centre (AC) and to preserve secret chip data in a more secure manner. According to the invention, final data is only written on the chip when the subscriber logs into a subscriber network. One advantage is that only initial data is written into the card enabling the customer to contact the computer centre of the information provider. During first contact the final data is traded between the card and the computer centre and written into the card. The computer centre is simply required to manage cards which have really been issued to customers.

System for transmitting information such as from a road sign to a vehicle using a sensor and a receiver

Abstract: The system transmits information such as from a road sign to a vehicle. The system includes at least one transmitter/receiver unit (10) which can be carried in the vehicle and at least a second transmitter/receiver unit (1) which is stationary e.g. attached to or near the road sign. Information is transmitted from the second transceiver unit to the mobile unit in the vehicle. In dependence on the information, the system can be adapted to control operation of the vehicle e.g. to regulate its speed and to display the information inside the vehicle. Independent claims also cover a method for transmitting the road sign information.

Terminal device and method for using different services offered via a telecommunications network

Abstract: A terminal device for using different services offered via a telecommunications network includes at lest one receiving device for image and sound information, at least one transmitting device for data which is used to select the received image and sound information, an input unit, a decoder for the image and sound information, and outputs for audio and video signals. A server for such terminal devices includes devices for connection to a telecommunications network, devices for carrying out authorization checks using the respective data received from a terminal device, and devices for receiving and processing service requests of the terminal devices. The services used may include television programs, such as pay TV and interactive television, and Internet applications.

System for using directory numbers with mobile phone, involves inputting several SIM cards for directory number bundling in mobile phone

Abstract: System for utilizing several directory numbers with a mobile phone having at least one phone card etc., bundling of the directory numbers in the mobile telephone or with the network provider, is carried out in the mobile phone by inputting several SIM-cards and the various directory numbers of the inputted SIM-cards are administered with an additional identifier in the mobile phone, and are communicated to the mobile phone network provider which is equipped with a recognition function and the bundled directory numbers are administered on the network side.

Method for compressing data

Abstract: In a method for compressing data, in which, in a data stream composed of characters, character strings are checked for correlation with other character strings that are present at a given distance in the data stream, and in which, in each case, the number of correlating characters and the position of the correlating characters within the respective other character string constitute the compressed data, at least one character is allowed to differ in the correlation check and data for correcting the at least one differing character is inserted into the compressed data.

Method and system for telecommunications based payment and accounting of fees

Abstract: Payment of charges for usage of a fee-payable section of road, is made in advance by debiting a virtual account. This virtual account is administered on a central computer (1) and is responsive to a mobile telecommunications terminal (MTK) (2) or an internet access via the telephone number of the MTK and/or an identity criterion (personal account number). The account is credited in prepaid mode by the purchase and enabling of money units. The establishment of an account and the enabling of a balance are performed by means of the telephone number of the MTK and/or the personal account number obtained when the money units were purchased. An Independent claim is also included for a system for payment and debiting of charges for the use of a vehicle in chargeable sections.

Why buffers in switching systems do not essentially improve QoS: an analytical case study for on/off source traffic

Abstract: Traffic models with a rate varying according to a Gaussian distribution are commonly used to evaluate statistical multiplexing in telecommunication systems. The superposition of a sufficient large number of homogeneous MarkovianOn-Off sources asymptotically approaches an Ornstein-Uhlenbeck process (OUP) which represents a Gaussian process with exponential autocorrelation function. We derive a simple expression for the bandwidth demand under QoS constraints which is close to numerical OUP/D/1 analysis results over the entire parameter region with relevance to applications. In comparison, results of the fluid flow method for fixed aggregation level are used to verify the OUP/D/1 asymptotics and to estimate its accuracy depending on the number of aggregated flows. Moreover, the OUP/D/1 asymptotics provides a useful check of the accuracy of bounds and approximations proposed in the literature in order to improve the effective bandwidth principle. Based on analytical evaluation, the efficiency of buffers for voice traffic is finally shown to be very limited, i.e. no more than 2% of bandwidth can be saved owing to buffers with regard to real time constraints and a predefined loss probability as QoS demands for voice.

Resetting sent information

Abstract: The invention relates to a method for operating a message memory (mobile box), which is connected to a telecommunications network, especially a telephone network and which is assigned to a subscriber terminal of an addressee that can be selected by an individual network indicator, and on which a sender can leave a message that is intended for and can be retrieved by the addressee. The sender has the ability to subsequently change the contents of a message left for the addressee after a prior authentication.

Method for the computer-assisted production of public keys for encoding information and device for carrying out said method

Abstract: A method for generating public keys for encrypting messages includes encrypting a message using a public key. The first message is capable of being decrypted using a private key associated with a recipient, the private key matching the public key. The public key includes a first and second part, the first part being the same for all recipients of the encrypted messages. The second part of the public key is determined using data that uniquely indicates the recipient.

Intelligent clothing item provided with sensor e.g. for monitoring vital functions of wearer, has sensor electrical line acting as antenna

Abstract: The clothing item, e.g. a closely fitting vest, has a sensor for measuring a condition and/or a body function of the person wearing the clothing item, provided with an integrated electrical line coupled to an electronic circuit for operation of the electrical line as an antenna, for contact between the sensor and the outside environment. An Independent claim for use of an electrical line integrated in a clothing item as an antenna is also included.

Verfahren zur Erhöhung der abgestrahlten Leistung bei der Übertragung digitaler Mehrträger-Signale mit AM-Sendern

Abstract: Fur die digitale Ubertragung mit bestehenden AM-Sendern wird seitens der ITU ein System mit Mehrtragerverfahren (OFDM) empfohlen. Digitale Mehrtrager-Signale haben aufgrund der Verteilungsdichte der Amplitudenwerte ein relativ groses Verhaltnis von maximaler Leistung zu effektiver Leistung (Crestfaktor), so dass der AM-Sender nur eine vergleichsweise geringe digitale Leistung abstrahlen kann. Auserdem verursacht der nichtlineare Mode des AM-Senders bei Ubersteuerung Innerband- und Auserbandstorungen. Durch eine Amplitudenbegrenzung fur das Amplitudensignal kann sowohl eine Verringerung des Crestfaktors als auch eine Minimierung der Innerband- und Auserbandstorungen erreicht werden. Die Amplitudenbegrenzung wird vorteilhaft vor der Umwandlung des komplexen I/Q-Signals in Amplitudensignal und phasenmoduliertes RF-Signal vorgenommen, um die enge Verkopplung zwischen Amplitudensignal und RF-Signal nicht zu storen. Auf diese Weise konnen nichtlineare Verzerrungen minimiert werden. Durch eine zusatzliche Filterung nach der Amplitudenbegrenzung wird das abgeschnittene I/Q-Signal verrundet, wodurch insbesondere Innerbandstorungen verringert werden konnen.

Method for preparing a restricted access service e.g. for pay-TV via mobilephone terminal, involves decoding message for testing reception validity in terminal device

Abstract: A method for preparing at least one restricted-access service involves initially providing a terminal device (3) for the user for communication via a telecommunication network (9), a transmitting device (2) is provided with a user-specific secret key(S1), followed by transmitting messages encoded with the secret key to the terminal device (3), and then decoded and messages for testing the reception authorization (ECM) are encoded with the secret key and passed to a decoder (1) for the user. The message for testing the reception validity (ECM) is then decoded in the terminal device (3) with the secret key (S1), and the pre-assigned reception parameters for handling the reception authorization (EMM) are compared with the reception parameters for testing the reception parameters authorization in the terminal device (3), and the decoded message for testing the reception authorization is passed to the decoder (1) in the event of agreement of the respective reception para meters. An Independent claim is included for a communication device.

Digital rights management system, where license key transmitted to user personal computer and stored in random access memory before being used to decrypt separately transmitted content

Abstract: Method for improving security in the encrypted transfer of content using a digital rights management system, whereby a license server transmits a license key over a secure data connection to a user personal computer where it is stored in RAM. The key is then used to decrypt separately transmitted content.