Lucent Technologies Inc.

Powerwave Technologies, Inc.

Motorola Corporation

Steven Andrew Wood

Ian Robert Johnson

Christian G Luke

Mark Cope

Adrian Richard Mansell

Jung Ah Lee

Qiang Cao

Xiaoyong Yu

Nicholas William Whinnett

Woodson Dale Wynn

Stephen Alan Allpress

Lorenz Fred Freiberg

Jie Lin

Michael Francis Garyantes

Karim Mhirsi

David Stuart Muirhead

Yue Lu

Lesley Phillip Sabel

Mario Zancan

Gregory J Wroclawski

Adrian Mansell

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. Another aspect of the disclosed invention is the ability to operate with very low transmit power and loop gain levels, allowing accurate gain control during such scenarios as cell initialization, that require operation over a wide dynamic range.

System and method for forward path gain control in a digital predistortion linearized transmitter

A system and method for rapidly correcting the time difference between two signals is disclosed. In particular, a system and method for very rapidly correcting timing errors to the very high degree of accuracy required for digital predistortion adaptation is disclosed. The method is a signal processing technique, which can be performed in either hardware or software, which employs a correlation computation. The correlation results are processed in a manner that enables very rapid and accurate estimation of the time difference between the two signals.

System and method for digital timing error correction in a communications system utilizing adaptive predistortion

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.

System and method for differential IQ delay compensation in a communications system utilizing adaptive AQM compensation

The invention relates to an error correcting decoder apparatus () and method. The decoder apparatus () comprises a likelihood estimator () which generates a sequence of bit value likelihood estimates, such as log likelihood ratios, for multi bit symbols of a data sequence. The decoder apparatus () further comprises a decoder element (), such as a Maximum A Priori (MAP) or appropriate Soft Output Viterbi decoder. The decoder element () generates a decoded data sequence in response to the bit value likelihood estimates. The decoder apparatus () also comprises a weighted processor () which generates a weighted compensation data sequence from the decoded data sequence. The weighted compensation data is used to modify the sequence of bit value likelihood estimates. The decoding is subsequently repeated using the improved bit value likelihood estimates whereby improved decoding performance is achieved. The invention may be applied to a two decoder element decoding apparatus () and may specifically be applied to turbo decoders.

Iterative decoding with likelihood weighting

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.

Radio communication system using wideband code division multiple access (WCDMA)

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.

Time division multiplexed rake finger for W-CDMA

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.

Segmented architecture for multiple sequence detection and identification in fading channels

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.

Time division multiple access communication system

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Hotwells, United Kingdom

Steven Andrew Wood