Abstract: Interference cancellation circuitry is provided for reconstructing a wirelessly transmitted modulated signal in a receiver using output of a decoder for calculating per-bit probabilities corresponding to bit-by-bit estimates of a coded message from which one bit hard decisions and multi-bit soft decision can be derived. A soft modulator reconstructs the transmitted modulated signal by calculating a weighted superposition depending upon the hard decisions and at least one combined value computed by combining two or more of the multi-bit soft decisions corresponding to different bits of the coded message. A soft modulation method using combined value(s) in a weighted superposition of hard decisions and computer program code for calculating the combined values and regenerated modulated signal are also provided. Other embodiments may be described and claimed.

Abstract: Interference cancellation circuitry is provided for reconstructing a wirelessly transmitted modulated signal in a receiver using output of a decoder for calculating per-bit probabilities corresponding to bit-by-bit estimates of a coded message from which one bit hard decisions and multi-bit soft decision can be derived. A soft modulator reconstructs the transmitted modulated signal by calculating a weighted superposition depending upon the hard decisions and at least one combined value computed by combining two or more of the multi-bit soft decisions corresponding to different bits of the coded message. A soft modulation method using combined value(s) in a weighted superposition of hard decisions and computer program code for calculating the combined values and regenerated modulated signal are also provided. Other embodiments may be described and claimed.

Abstract: A system and method for controlling the gain in the forward signal path of a digital predistortion linearizer is disclosed. The loop gain of the predistortion system is driven to unity, where a separately controlled constant-gain observation path allows accurate gain control of the forward path. This is divided into digital gain from the predistortion function and analog gain from a Voltage Variable Attenuator (VVA) in the transmitter. The invention balances the distribution between these two domains in order to maximize dynamic range and minimize noise in the forward signal path. In order to distribute the forward path gain accurately, the characteristic of the VVA must be well known. Since these devices tend to be non-linear, with variable characteristic over temperature and batch, the invention compensates for this non-linear behavior by tracking the varying transfer characteristic of the VVA, giving a predictable local characteristic.

Abstract: A system and method for compensating for the time delay between the in-phase I and the quadrature Q paths of a digitally modulated transmitter incorporating an analog quadrature modulator is disclosed. The time delay between the in-phase I and the quadrature Q paths is computed and used to calibrate a set of interpolation filters in the forward path that compensate for this delay, reducing the frequency dependent degradation in performance of the analog quadrature modulator. The disclosed system and method provides improved compensation of gain, phase and DC offsets in the analog quadrature modulator over a broader bandwidth. Fractional delay interpolation filters may be used to estimate the delay between the in-phase and quadrature paths. This eliminates the need for a factory calibration procedure, speeding up manufacture and reducing costs.

Abstract: A third generation general partnership program radio communication system or a universal mobile telephone system employs a wide band code division multiple access system. The codes in various incoming signals from different sources are identified by cross correlation using a code matched filter. A multiplexer, samples the signals from each of the P sources at P times the chip rate of the codes in the incoming signals. The mutliplexer time multiplexes the received signals and feeds them to single delay line consisting of N stages each having P elements. Each stage will thus store one sample from each of the P sources. A selected element in each stage has an output which feeds a corresponding input of a code matched filter dot-product adder chain to enable a cross-correlation to be established for each incoming signal in turn.

Abstract: A method of recovering transmitted symbols in a receiver of a spread spectrum system, comprising: receiving a signal including multi-path components associated with transmitted symbols; de-spreading successive separate portions of the received signal to provide a symbol estimate based on each multipath component, wherein the de-spreading step comprises determining at least one partial estimate of at least one transmitted symbol for an at least one partial multi-path component contained in a separate portion; and summing the partial estimates of separate portions corresponding to a same transmitted symbol.

Abstract: Known sequences are detected and identified in a fast fading environment using a segmented correlator and FHT (Fast Hadamard Transform) architecture. The incoming sequence of samples or data is segmented into blocks. Each block is individually detected using a correlator/FHT segment. Each sequence identifying output of each correlator/FHT segment is summed with the corresponding output of other correlator/FHT segments. Each sum is compared with a threshold to determine whether a particular sequence has been detected and identified.

Abstract: A time division multiple access communication system is disclosed, in which down link data are transmitted over a data channel in repeated time frames each containing a plurality of time slots. Down link set up information is transmitted over a control channel to indicate from which time slot a user terminal should extract data. Each frame on the data channel includes a user packet flag to indicate whether or not each time slot in the frame contains data. Each user terminal is responsive to the set up information and to the user packet flags to extract data from its assigned time slot in those frames which the slot is indicated to contain data.

Abstract: A third generation general partnership program radio communication system or a universal mobile telephone system employs a wide band code division multiple access system. The codes in various incoming signals from different sources are identified by cross correlation using a code matched filter. A multiplexer, samples the signals from each of the P sources at P times the chip rate of the codes in the incoming signals. The mutliplexer time multiplexes the received signals and feeds them to single delay line consisting of N stages each having P elements. Each stage will thus store one sample from each of the P sources. A selected element in each stage has an output which feeds a corresponding input of a code matched filter dot-product adder chain to enable a cross-correlation to be established for each incoming signal in turn.

Abstract: According to the present invention there is provided a method of recovering transmitted symbols in the receiver of a spread spectrum system, comprising: receiving a signal including multi-path components associated with a transmitted symbol; de-spreading successive portions of the received signal to provide a symbol estimate based on each multi-path, wherein at least one multi-path of the transmitted symbol is contained in separate portions, the de-spreading step further comprising determining a partial estimate of the transmitted symbol for the at least one multi-path component based on each part of the multi-path contained in each separate portion; and summing said partial estimates.