Abstract: A reception unit for use in a data link and a method for error correction on a reception word in a data link are specified. A low-density parity-check code, LDPC code, is used to iteratively adapt the reception word by virtue of bit node messages and check node messages being exchanged. The check node messages that are transmitted to the bit nodes are quantized in three levels and adopt the values ?1, 0 or +1. The method may thus be implemented with low computational expenditure.

Abstract: A transmitter (200) for transmitting radio signals comprising a digital signal source (102), a compensation unit (104), two digit al-to-analogue converters (106) and (108), an analogue modulator (110), an amplifier (112) an antenna (114) connected to the amplifier (112), the transmitter further comprises a front-end unit (220) connected to an estimator (230). Said front-end unit (220) comprises a mixer operably (302) connected to a local oscillator (304), an analogue-to-digital converter (306) for processing signal received from the mixer (302), a first digital filter (308) for converting signal received from the analogue-to-digital converter (306) to a baseband signal, an adaptive digital filter (310) operable to time-synchronise its output signal (z(k)) to a reference signal (r(k)) and to remove linear distortions from the signal received from the first digital filter.

Abstract: A transmitter (200) for transmitting radio signals comprising a digital signal source (102), a compensation unit (104), two digit al-to-analogue converters (106) and (108), an analogue modulator (110), an amplifier (112) an antenna (114) connected to the amplifier (112), the transmitter further comprises a front-end unit (220) connected to an estimator (230). Said front-end unit (220) comprises a mixer operably (302) connected to a local oscillator (304), an analogue-to-digital converter (306) for processing signal received from the mixer (302), a first digital filter (308) for converting signal received from the analogue-to-digital converter (306) to a baseband signal, an adaptive digital filter (310) operable to time-synchronise its output signal (z(k)) to a reference signal (r(k)) and to remove linear distortions from the signal received from the first digital filter.

Abstract: To calibrate a transmitter and/or sender for controlling a beam forming network, each of the control signals is divided into a plurality of frequency segments. The control signal of each frequency segment is multiplied by complex coefficients so that the transmitter output signals, after passing through a reference receiver, are identical to the respective control signals. A similar adjustment is performed for the receive direction. The method and the device allow the same beam characteristic.

Abstract: A method of synchronizing carrier frequencies in a mobile radio network having base and mobile stations, in which a synchronization signal is radiated from the base stations, is received by the mobile stations and is used to derive the transmission frequency.A group of sinusoidal oscillations having different frequencies is emitted from each base station as a synchronization signal. The mobile stations each have a matched filter, with which at least one of the transmitted sinusoidal oscillations can be found and detected.The method is insensitive to fading, and permits an extensive normalization of the circuits in the base stations and, in particular, permits a unified evaluation in the mobile stations.

Abstract: A method for reliability-controlled data detection of TDMA data bursts with a central test sequence for determining the identification parameters of the transmission channel, wherein: the data segments adjoining the test sequence at both ends are subdivided into N sectors A.sub.i, i=.+-.1, . . . ,.+-.N, with M sampled signal values each; in the kth processing step the sectors A.sub.1+, +1.ltoreq.i.sup.+ .ltoreq.=N are detected, suitable measures .LAMBDA..sub.i- and .LAMBDA..sub.i+ are determined for the detection results, and the detection result of the sector whose measure of reliability has the smaller value is rejected again if by then all sectors A.sub.-1, . . . , A.sub.i-+1 and A.sub.+1, . . . , A.sub.i+-1 have finally been processed; in the kth processing step the sector A.sub.i- is detected if -N<i.sup.- .ltoreq..sup.- 1 and all the sectors A.sub.i+, +1.ltoreq.i.sup.+ .ltoreq.+N have already been processed; in the kth processing step the sector A.sub.i+ is detected if +1.ltoreq.i.sup.

Abstract: A method for adaptation to the time-variable channel impulse response during a burst in receivers for TDMA mobile radio systems, each burst including in the center a test sequence which is known to the receiver and by means of which an initial estimate of the channel impulse response is possible, whereinthe received signal of a burst is suitably sampled,the received burst is divided in 2N+1 sectors A.sub.-N, . . . , A.sub.+N, it being assumed that the channel impulse response can be regarded as being constant within a sector,a vector x of dimension (2N+1)L is defined, L being the number of channel impulse response coefficients and the (iL+l)-th component of x, -N.ltoreq.i.ltoreq.+N, 0.ltoreq.l.ltoreq.L-1 is initialized before the start of the detection using the l-th coefficient of the estimated value of the channel impulse response obtained from the test sequence, Matrices E, E.sub.i, E.sub.ii, S and vectors x.sub.i, d, r.sub.