Abstract: The invention relates to a weighting circuit for a receiver (1), which is designed to receive a multi-carrier signal consisting of carrier signals. According to the invention, the carrier signals are weighted by the weighting circuit (18) in such a way that the parasitic signal energy has the same intensity in all weighted carrier signals. In a preferred embodiment of the invention, the weighting circuit comprises at least one multiplier that multiplies an assigned a carrier signal by a stored weighting co-efficient. The stored weighting coefficients constitute reliability information for the various carrier signals.

Abstract: In an OFDM-based transmission method it can be stated for the preamble (4, 7) of a data packet that its N preamble segments (B, B) are obtained from the segment-by-segment multiplication of an initial segment, which is fixed for all N preamble segments, by a multiplication sequence with a length of N elements. It can be stated for the OFDM data symbols that a plurality of OFDM symbols which are transmitted successively in time each include at least one pilot signal, with the respective subcarrier which transmits the at least one pilot signal being dependent on the time index of the espective OFDM symbol.

Abstract: A common phase value of pilot subcarriers of a received data symbol (n) is estimated and used for correcting the phase of all subcarriers of the data symbol, wherein, with a time-variant frequency of the local oscillator (VCO), the estimated noisy phase values (?n) are used directly for the phase and frequency correction, whereas with a time-invariant frequency after the VCO, a corrected phase value ({circumflex over (?)}n) is determined from the estimated phase values of the current data symbol (?n) and earlier data symbols (?m) in a linear FIR filter arrangement (17-20) and is used for the phase correction.

Abstract: In a method for channel estimation of an OFDM signal transmitted via a channel, an initial channel transfer function is calculated by channel estimation. A channel impulse response is calculated on the basis of the initial channel transfer function. Values of the channel impulse response or of a filtered channel impulse response are classified as noise or as a signal as a function of the level of the values of the channel impulse or of the level of the values of the filtered channel impulse response. A noise-reduced channel impulse response is calculated on the basis of the channel impulse response using the classification, and a noise-reduced channel transfer function is calculated on the basis of this noise-reduced channel impulse response.

Abstract: In an OFDM-based transmission method it can be stated for the preamble (4, 7) of a data packet that its N preamble segments (B, B) are obtained from the segment-by-segment multiplication of an initial segment, which is fixed for all N preamble segments, by a multiplication sequence with a length of N elements. It can be stated for the OFDM data symbols that a plurality of OFDM symbols which are transmitted successively in time each include at least one pilot signal, with the respective subcarrier which transmits the at least one pilot signal being dependent on the time index of the respective OFDM symbol.

Abstract: A method for an operating system including a channel estimation for OFDM systems in a receiver is disclosed. One embodiment provides information indicative of multiple transmitter signals reception characteristics of signals received from multiple transmitters. Then, channel estimation is performed dependent on the information.

Abstract: The channel estimates for the subcarriers are used to determine the signal strength distribution in the form of a cumulative histogram. The latter is used to determine, as a signal strength threshold value E, that maximum signal strength whose magnitude is less than or equal to the signal strengths of a predetermined number L of subcarriers which are to be limited, i.e. saturated, in the signal processing path. The signal strength threshold value E and a constant K are used to form a multiplication factor M with which the data signals are weighted or by which the data signals are multiplied, the L subcarriers being limited to a fixed value after multiplication.

Abstract: A device (10) for preamble detection and frame synchronization, wherein data packets are transmitted by radio between transmitter and receiver and the data packets are in each case preceded by a known preamble with a sequence of preamble sections (B), with a correlator unit (20) for correlating samples (rn) with a preamble section (B), an accumulator unit (23) for accumulating correlation results, and a detector unit (24) for detecting a received preamble by a comparison of the accumulation result with a threshold value.

Abstract: A method and apparatus is provided for processing a received orthogonal frequency division multiplexing (OFDM) signal at a receiver, wherein said signal has been distorted by one or more transmission bursts from a transmitter. The method and apparatus generate a phase compensated OFDM signal based upon a pre-fast fourier transform (pre-FFT) phase progression estimate and information regarding timing of the one or more transmission bursts.

Abstract: A method of channel estimation and a channel estimator for a multiple carrier radio transmission system is described. The method comprises receiving a signal comprising a symbol-carrier matrix, the symbol-carrier matrix comprising a pre-determined pattern of pilot symbols, and determining first channel estimates at pilot symbol positions of the pilot symbols in the symbol-carrier matrix. The method further comprises determining second channel estimates at intermediate positions of the symbol-carrier matrix, wherein the intermediate positions are separated from the pilot symbol positions of the pilot symbols by positions associated with non-determined channel estimates and determining third channel estimates at further positions of the symbol-carrier matrix.

Abstract: The invention proposes a transmission/reception arrangement (1) which contains a respective distortion unit (5, 6) for the transmission and reception paths (2, 3) and also a calibration apparatus (7). By sending a test signal in an operating mode for calibration and returning the test signal processed in the transmission path (2) to the reception path, it is possible to evaluate the error signals in the transmission and reception paths. In line with the principle proposed, this is done by evaluating the spectral components of the returned received signal which each represent single sources of error in the transmission or reception path. This allows calculation of calibration parameters for suppressing these errors both in the transmission path and in the reception path.

Abstract: A method for an operating system including a channel estimation for OFDM systems in a receiver is disclosed. One embodiment provides information indicative of multiple transmitter signals reception characteristics of signals received from multiple transmitters. Then, channel estimation is performed dependent on the information.

Abstract: In a method for channel estimation of an OFDM signal transmitted via a channel, an initial channel transfer function is calculated by channel estimation. A channel impulse response is calculated on the basis of the initial channel transfer function. Values of the channel impulse response or of a filtered channel impulse response are classified as noise or as a signal as a function of the level of the values of the channel impulse or of the level of the values of the filtered channel impulse response. A noise-reduced channel impulse response is calculated on the basis of the channel impulse response using the classification, and a noise-reduced channel transfer function is calculated on the basis of this noise-reduced channel impulse response.

Abstract: A method for carrier frequency tracking of a received signal having a burst structure includes dividing each burst into a number of segments. The carrier frequency offset of a first segment within a burst is measured to obtain a first segment carrier frequency offset measurement value. The carrier frequency offset of a second segment within the burst is corrected by a second segment carrier frequency offset correction value based on the first segment carrier frequency offset measurement value.

Abstract: A method and apparatus is provided for processing a received orthogonal frequency division multiplexing (OFDM) signal at a receiver, wherein said signal has been distorted by one or more transmission bursts from a transmitter. The method and apparatus generate a phase compensated OFDM signal based upon a pre-fast fourier transform (pre-FFT) phase progression estimate and information regarding timing of the one or more transmission bursts.

Abstract: A device (10) for preamble detection and frame synchronization, wherein data packets are transmitted by radio between transmitter and receiver and the data packets are in each case preceded by a known preamble with a sequence of preamble sections (B), with a correlator unit (20) for correlating samples (rn) with a preamble section (B), an accumulator unit (23) for accumulating correlation results, and a detector unit (24) for detecting a received preamble by a comparison of the accumulation result with a threshold value.

Abstract: A common phase value of pilot subcarriers of a received data symbol (n) is estimated and used for correcting the phase of all subcarriers of the data symbol, wherein, with a time-variant frequency of the local oscillator (VCO), the estimated noisy phase values (?n) are used directly for the phase and frequency correction, whereas with a time-invariant frequency after the VCO, a corrected phase value ({circumflex over (?)}n) is determined from the estimated phase values of the current data symbol (?n) and earlier data symbols (?m) in a linear FIR filter arrangement (17-20) and is used for the phase correction.

Abstract: The invention relates to a weighting circuit for a receiver (1), which is designed to receive a multi-carrier signal consisting of carrier signals. According to the invention, the carrier signals are weighted by the weighting circuit (18) in such a way that the parasitic signal energy has the same intensity in all weighted carrier signals. In a preferred embodiment of the invention, the weighting circuit comprises at least one multiplier that multiplies an assigned a carrier signal by a stored weighting co-efficient. The stored weighting coefficients constitute reliability information for the various carrier signals.

Abstract: In an OFDM-based transmission method it can be stated for the preamble (4, 7) of a data packet that its N preamble segments (B, {overscore (B)}) are obtained from the segment-by-segment multiplication of an initial segment, which is fixed for all N preamble segments, by a multiplication sequence with a length of N elements. It can be stated for the OFDM data symbols that a plurality of OFDM symbols which are transmitted successively in time each include at least one pilot signal, with the respective subcarrier which transmits the at least one pilot signal being dependent on the time index of the espective OFDM symbol.

Abstract: The invention proposes a transmission/reception arrangement (1) which contains a respective distortion unit (5, 6) for the transmission and reception paths (2, 3) and also a calibration apparatus (7). By sending a test signal in an operating mode for calibration and returning the test signal processed in the transmission path (2) to the reception path, it is possible to evaluate the error signals in the transmission and reception paths. In line with the principle proposed, this is done by evaluating the spectral components of the returned received signal which each represent single sources of error in the transmission or reception path. This allows calculation of calibration parameters for suppressing these errors both in the transmission path and in the reception path.