Showing papers by "Deutsche Telekom published in 1993"

Process for allocating frequencies to base stations of a mobile radiotelephone network.

Abstract: A process for allocating frequencies to base stations of a mobile radiotelephone network is based on input information which contains at least the number of frequencies required for each base station, the admissible frequencies in the mobile radiotelephone network and information on possible interference effects between the base stations in the event of similar and/or contiguous frequencies. The following steps are alternatively carried out: (a) a base station among the plurality of base stations to which not all available frequencies have yet been allocated is selected according to a first base station selection criterion and if required further base station selection criteria; (b) a frequency is selected according to a first frequency selection criterion and if required further frequency selection criteria; (c) the frequency selected during step (b) is identified as allocated to the base station selected during step (a).

Procedure for defining position by means of an asynchronous cellular mobile radio system

Abstract: The procedure for defining position by means of an asynchronous cellular mobile radio system is dependent on only minor additional costs for its use. The parameters required for defining position are reported to the mobile radio terminal even while the connection is being set up, for technical radio reasons. Only minor changes are carried out in the mobile radio terminal. By evaluating range-dependent parameters which are reported continuously to the mobile radio terminal whenever a connection is set up and in order to maintain the connection, it is not only possible to identify the radio cell in which the mobile radio terminal is located, but the location accuracy can be improved down to a circular ring. Data from adjacent radio cells are included in the calculation to decide on a circular ring segment from a circular ring.

Method for enabling later verification of already transmitted data

Abstract: The method for enabling later verification of already transmitted data is based on the application of cryptographic methods for verifying the integrity and the authenticity of already transmitted personal data which have meantime been cleared (deleted). The transmitting entity transmits the data to a further entity, which confirms the unfalsified reception of the data. After the calculation of a cryptographic check sum with the use of a secret key, the transmitted data are cleared in the transmitting entity. In the event of renewed occurrence of the data in the transmitting entity, the cryptographic check sum and the secret key can be used to verify the integrity and authenticity of the data.

TiOxCy Thin Film Deposition by CO2+-Ion Beam Sputtering of Titanium

Abstract: Titanium metal is sputtered by ion beams using a Kaufman-type ion source with carbondioxide as working gas. Deposition takes place on watercooled substrates of silicon and InP. The films obtained are amorphous; they adhere excellently. SEM-pictures reveal a featureless dense fracture and a smooth surface. Despite a carbon content of 9 at% the films are highly transparent in the visible and near infrared wavelength range. Refractive indices center around 2.15 at values typically found for amorphous TiO2. The electrical properties are characterized by dielectric constant of e = 26 ± 3, leakage current densities at breakdown of jL = 3.65 · 10−3 A/cm2 and breakdown fields EB > 1 MeV/cm.