Abstract: The invention relates to a CDMA receiver for receiving, in a multiple subscriber environment, a CDMA signal transmitted with a chip rate by a transmitter via different signal paths of a physical transmission channel.

Abstract: A method is described for estimating channel impulse responses of a mobile radio channel with a broad bandwidth by a code division multiplexing method, and with a synchronization channel continuously transmitting sequences to mobile radio receivers. The sequences are provided for synchronization of each mobile radio receiver and are known to each of the mobile radio receivers. The transmitted sequences have pilot symbols for identifying the synchronization channel, and the pilot symbols are transmitted at points that are known to the receivers within a time slot. When searching for and identifying the synchronization channel, the pilot symbols and, possibly, further symbols and sequences which are known in the receivers, are evaluated to estimate the delay times and the complex amplitudes, of the mobile radio channel responses.

Abstract: A circuit configuration has a radio-frequency section with a receiving mixing stage, and has a signal processing circuit with an A/D converter, a digital filter and a frequency estimator. The frequency estimator continuously determines a first frequency correction control signal, which is representative of a frequency offset between the frequency of an IF received signal and a frequency which is characteristic of a pass band of the filter. The first frequency correction control signal is used for readjustment of the mixing frequency.

Abstract: A method for estimating a channel impulse response of a mobile radio channel is described. The mobile radio channel is accessed over a wide bandwidth by a code division multiplex method. A second mobile radio channel continuously transmits sequences to a multiplicity of mobile radio receivers, and the sequences are known to each of the multiplicity of mobile radio receivers. The delay parameters of the mobile radio channel are estimated using the sequences transmitted via the second mobile radio channel. The mobile radio receiver is adjusted in accordance with the delay parameters estimated and weighting factors of the mobile radio channel are determined.

Abstract: A circuit configuration for a multistandard communications terminal has, for the reception of radio signals, a radio frequency component with a receive conversion stage and a signal-processing circuit connected downstream of the radio frequency component. The signal-processing circuit has an A/D converter and a digital filter. The pass-band of the digital filter is variable. In operation, the pass-band is set according to a selected system standard of the received radio signals.

Abstract: A device for carrying out search procedures includes a memory for storing a digital received data sequence, and a memory storing a predetermined correlation data sequence. A correlation device has a first section, in which sequence elements of the received data sequence are correlated with sequence elements of the correlation data sequence. A variable number K of sequence element correlation results are summed in the second section, in order to form an accumulated correlation result.

Abstract: A code word generator for OVSF codes, comprising an intermediate memory device (16) which is used to input a calculation index as a binary calculation index data word, a calculation device (17) which permutes the significant data bits of the calculation index data word bit-by-bit so that a calculation basis (B) can be generated, a counter (21) for producing a counting variable (Z) and provided with a logic circuit comprising several AND gates for bit-by-bit linkage of the counting variables (Z) generated with the calculation basis (B) in order to form a linking data word and several XOR gates for logical reduction of the linking data word to form code word data bits of the OVSF code word.

Abstract: In a method according to the invention, N data symbols of a subscriber signal form a block. In a first method step, the block is divided into a plurality of partial blocks having Ns data symbols. The Ns data symbols are then allocated to sub-carriers and are modulated in parallel onto the various sub-carriers, the modulation being carried out for each of the sub-carriers with at least one individual code symbol. The sub-carriers are heterodyned to form a broadband carrier, so that the Ns data symbols are transmitted simultaneously. The transmission then takes place in N/Ns successive partial blocks via the radio interface.

Abstract: Transmission data that will be transmitted is coded and thus band-spread using a spread code. The band-spread transmission data is also coded using a scrambling code. The scrambling process is followed by pulse shaping, frequency correction, and DC offset and/or amplitude compensation for the band-spread and scrambled transmission data.

Abstract: A quality of service on transmission channels in a digital transmission system is assessed. A turbo coding is carried out in a turbo coder at the transmitter end for channel coding. A turbo decoding is carried out in a turbo decoder with soft-decision output signals at the receiver end. The quality of service is determined from the variances of the soft-decision output signals from the turbo decoder. If a MAP (maximum a posteriori) symbol estimator is used at the receiver end, the quality of service is determined from the variance &sgr;2LLR of the log-likelihood ratio LLR of the soft-decision output signals from the turbo decoder. The variances &sgr;2LLR are used to calculate the bit error rate as a measure of the quality of service. An RCPTC (Rate Compatible Punctured Turbo Code) is used as the turbo code for the method and in the device for assessing the quality of service.

Abstract: In a method for transmitting data in a digital transmission system given packet-switched service, for purposes of channel coding, a turbo-coding is performed in a turbo-coder at the sender side and a turbo-decoding with soft decision output signals is performed in a turbo-decoder at the receiver side. To trigger an ARQ, the channel quality is estimated by a parameter estimation method; the variances of the soft decision output signals at the turbo-decoder are determined; the correctness or respectively, defectiveness of the transmitted packet is inferred from the channel quality and the variances; and a retransmission of at least a part of defective packet is triggered. In the retransmission of the information of a defective packet, at least part of the information suppressed by the dotting in the precious transmission is sent. This additional information is [. . .] inserted into the already existing information at the receiver side, and this complete information is decoded again.

Abstract: A code word generator for OVSF codes, comprising an intermediate memory device (16) which is used to input a calculation index as a binary calculation index data word, a calculation device (17) which permutes the significant data bits of the calculation index data word bit-by-bit so that a calculation basis (B) can be generated, a counter (21) for producing a counting variable (Z) and provided with a logic circuit comprising several AND gates for bit-by-bit linkage of the counting variables (Z) generated with the calculation basis (B) in order to form a linking data word and several XOR gates for logical reduction of the linking data word to form code word data bits of the OVSF code word.

Abstract: A turbo-code decoder with iterative channel parameter estimation for decoding turbo-coded received data that includes systematic information data and redundant data. The turbo-code decoder includes a weighting circuit for weighting the turbo-coded received data with at least one estimated channel parameter. Estimated value data is generated. A turbo-code coding circuit turbo-codes the generated estimated value data. A comparison circuit compares the turbo-coded estimated value data with the turbo-coded received data, and depending on the result of the comparison, iteratively sets the estimated channel parameter(s) in order to weight the turbo-coded received data.

Abstract: In a method for packet transmission using an ARQ protocol on transmission channels in a digital transmission system, for channel coding, turbo coding is carried out in a turbo coder at the transmitter end and turbo decoding is carried out in a turbo decoder at the receiver end using soft-decision output signals. A return channel is provided, which the receiver uses to request the information from faulty packets once again. An RCPTC is used as the turbo code. When the information in a faulty packet is retransmitted, at least a portion of the information suppressed by the puncturing of the RCPTC in the previous transmission is transmitted. This additional information is inserted into the already existing information at the receiver end, and this completed information is decoded once again. When the repeat transmission is made, the only bits which are transmitted are those which are additionally available at the next lower coding rate, since they are not punctured.

Abstract: Convolutional codes are decoded by calculating, for uncoded and coded symbols, a first and/or second item of reliability information (&Lgr;u and &Lgr;c respectively). The item of reliability information is representative of the probability that the considered nth uncoded or coded symbol is equal to a value i of the symbol set, under the condition that a specific sequence of received coded symbols is present. An approximate expression is proposed for calculating the second item of reliability information.

Abstract: A turbo-code decoder with iterative channel parameter estimation for decoding turbo-coded received data that includes systematic information data and redundant data. The turbo-code decoder includes a weighting circuit for weighting the turbo-coded received data with at least one estimated channel parameter. Estimated value data is generated. A turbo-code coding circuit turbo-codes the generated estimated value data. A comparison circuit compares the turbo-coded estimated value data with the turbo-coded received data, and depending on the result of the comparison, iteratively sets the estimated channel parameter(s) in order to weight the turbo-coded received data.

Abstract: A receiver circuit for a communications terminal includes a signal pre-processing circuit having: an analog/digital converter device with K analog/digital converters connected in parallel, a conversion device, and a filter device connected downstream of the conversion device. The filter device has N digital filters connected in parallel, where N is an integer that is greater than or equal to 1 and is less than K.

Abstract: A method for equalizing and decoding an error-protected data signal transmitted via a radio channel is described. According to the method, an equalized data signal is calculated at the receiving end in a demodulator with a first channel estimator. The equalized data signal is decoded by a decoder to determine a decoded output signal. The equalized data signal is transmitted to a second channel estimator, which repeatedly detects second channel parameters of the radio channel. The parameters are transmitted to the decoder which uses them as calculation parameters during decoding.

Abstract: The new CDMA (Code Division Multiple Access) system structure which is equivalent to the structure of a CDMA system operating with direct code spread (DS, Direct Sequence) but operates with multicarrier (MC) methods. The multicarrier method is introduced a suitable selection of the spread code, with the result that the production of signals in CDMA systems with DS and with MC is harmonized and JD (Joint Detection) multisubscriber detection methods, which are known per se, with or without diversity reception can be used.

Abstract: In a method for data transmission on transmission channels in a digital transmission system, turbo coding is carried out in a turbo coder at a transmitter end for channel coding, and turbo decoding with soft-decision output signals is carried out in a turbo decoder at the receiver end. In order to improve the quality of service, the quality of service is determined from the variances of the soft-output signals at the turbo decoder, and the coding rate is set by adaptation of the puncturing such that a predetermined quality of service is obtained. Alternatively, the number of decoding iterations is set as a function of the quality of service. If a MAP symbol assessor is used at the receiver end, the variances &sgr;2LLR of the soft-decision output signals from the turbo decoder are determined, and the bit error rate is calculated from the variances &sgr;2LLR as a measure of the quality of service.