Abstract: OFDM symbols are generated using data from one or more users or from one or more data sources represented on a number of sub-carriers. To inhibit multiple-access interference on application of the CDMA principle, the data are transformed in a data-source specific manner and only subsequently allocated to the sub-carriers, independently of the transformation.

Abstract: A method and a device for determining an unabbreviated channel-impulse response in an OFDM transmission system, of which the duration is greater than the length of the guard interval, estimates the channel-transmission factor at frequency-time positions of a relatively-coarse frequency-time raster, interpolates the channel-transmission factor at frequency-time positions of a relatively-fine frequency-time raster and calculates the unabbreviated channel-impulse response by means of inverse Fourier transform from the estimated or interpolated values of the channel-transmission factor at the frequency-time positions of the relatively-fine frequency-time raster. In this context, estimated values of the channel-transmission factor optimized at the individual frequency-time positions of the relatively-fine frequency-time raster are determined from received symbols and from transmitted symbols estimated by means of decision from the received symbols.

Abstract: OFDM symbols are generated using data from one or more users or from one or more data sources represented on a number of sub-carriers. To inhibit multiple-access interference on application of the CDMA principle, the data are transformed in a data-source specific manner and only subsequently allocated to the sub-carriers, independently of the transformation.

Abstract: OFDM symbols are generated using data from one or more users or from one or more data sources represented on a number of sub-carriers. To inhibit multiple-access interference on application of the CDMA principle, the data are transformed in a data-source specific manner and only subsequently allocated to the sub-carriers, independently of the transformation.

Abstract: Data is transmitted via time division multiple access methods and every radio cell includes one base station each for the radio coverage of a plurality of mobile stations assigned to the radio cell. The base station receives, in addition to mobile station signals of its own radio cell, mobile station signals of neighboring radio cells and determines, on the basis of the mobile station signals received, a time synchronization value and/or a frequency synchronization value to which the base station synchronizes itself.

Abstract: Data is transmitted via time division multiple access methods and every radio cell includes one base station each for the radio coverage of a plurality of mobile stations assigned to the radio cell. The base station receives, in addition to mobile station signals of its own radio cell, mobile station signals of neighboring radio cells and determines, on the basis of the mobile station signals received, a time synchronization value and/or a frequency synchronization value to which the base station synchronizes itself.

Abstract: OFDM symbols are generated using data from one or more users or from one or more data sources represented on a number of sub-carriers. To inhibit multiple-access interference on application of the CDMA principle, the data are transformed in a data-source specific manner and only subsequently allocated to the sub-carriers, independently of the transformation.

Abstract: OFDM symbols are generated using data from one or more users or from one or more data sources represented on a number of sub-carriers. To inhibit multiple-access interference on application of the CDMA principle, the data are transformed in a data-source specific manner and only subsequently allocated to the sub-carriers, independently of the transformation.

Abstract: A method and a device for determining an unabbreviated channel-impulse response in an OFDM transmission system, of which the duration is greater than the length of the guard interval, estimates the channel-transmission factor at frequency-time positions of a relatively-coarse frequency-time raster, interpolates the channel-transmission factor at frequency-time positions of a relatively-fine frequency-time raster and calculates the unabbreviated channel-impulse response by means of inverse Fourier transform from the estimated or interpolated values of the channel-transmission factor at the frequency-time positions of the relatively-fine frequency-time raster. In this context, estimated values of the channel-transmission factor optimized at the individual frequency-time positions of the relatively-fine frequency-time raster are determined from received symbols and from transmitted symbols estimated by means of decision from the received symbols.

Abstract: Data is transmitted via time division multiple access methods and every radio cell includes one base station each for the radio coverage of a plurality of mobile stations assigned to the radio cell. The base station receives, in addition to mobile station signals of its own radio cell, mobile station signals of neighboring radio cells and determines, on the basis of the mobile station signals received, a time synchronization value and/or a frequency synchronization value to which the base station synchronizes itself.

Abstract: A method and OFDM receiver are provided for reducing the influence of harmonic interference on OFDM transmission systems, wherein high interference unity is achieved by the simultaneous use of a window function and a determined item of reliability information, the window function being a Nyquist-shaped window function which generates low side lobes in the subcarrier and interference spectra while simultaneously leaving the orthogonality of the subcarriers unchanged, the determined item of reliability information being derived from a measurement when transmitting a so-called zero symbol, in order to detect the instantaneously active interference signals, with the high interference immunity being achieved when the subcarrier-specific information is taken into account in a so-called Viterbi decoder.

Abstract: A method synchronizes a radio communication system divided into radio cells. Data is transmitted in the radio communication system by a multiple access method. Each radio cell thus has a base station for the radio feed of several mobile stations, allocated to the radio cell. A synchronization of the base station is carried out using the received signals from mobile stations in the same radio cell and also in adjacent radio cells. The base station determines at least one pilot signal and signals said pilot signal to the allocated mobile stations in a downwards direction. The allocated mobile stations transmit the signaled pilot signal in an upwards direction to the base station. The base station determines a synchronization value, from the received pilot signals from the radio cell thereof and also from the adjacent radio cells, fro a time synchronization and/or for a frequency synchronization on which the bas station is synchronized.

Abstract: OFDM symbols are generated using data from one or more users or from one or more data sources represented on a number of sub-carriers. To inhibit multiple-access interference on application of the CDMA principle, the data are transformed in a data-source specific manner and only subsequently allocated to the sub-carriers, independently of the transformation.

Abstract: The invention relates to a method and device for improving, on the receive side, the transmission quality (residual/bit error rate) of a data transmission system, which is based on orthogonal frequency division multiplexing (OFDM) technology and which is negatively influenced by narrow-band harmonic interference signals. The invention takes into account two technical measures. In one technical measure, a received OFDM symbol is processed by means of a cyclic rotation of the OFDM receive symbol and of a subsequent Nyquist windowing in the time domain whereby leading to a reduction of the interference spectrum outside of the sub-carrier bandwidth. In the other technical measure, a channel estimation of the channel transmission function on the sub-carrier level is effected in parallel with the first technical measure, and the signal-to-noise ratio is calculated or estimated by estimating the interference power on the sub-carrier level.