Abstract: In a method of data transmission according to one embodiment of the invention, data transitions on adjacent conductors are separated in time. In a method of data transmission according to another embodiment of the invention, signals on adjacent conductive paths pass through different alternating sequences of inversions and regenerations. In a method of data transmission according to a further embodiment of the invention, data transitions having the same clock dependence are separated in space.

Abstract: A system and method for controlling modulation. The system includes a plurality of modulators and a transmitting unit. The plurality of modulators decodes data from a data signal and also encodes the data into a clock signal. The transmitting unit transmits the encoded clock signal. According to the system and method disclosed herein, the present invention provides optimized coding efficiency while minimizing overall power consumption.

Abstract: A method of synchronizing data in a communications system includes generating a composite signal comprising a serial stream of data partitioned in one or more frames, and transmitting the composite signal to a receiver. Multiphase clock signals are generated. The composite signal received at the receiver is compared with each of the multiphase clock signals until either sustained coincidence therebetween is achieved or sustained non-coincidence is achieved, thereby synchronizing the receiver to bit boundaries in the composite signal and to one or more of the clock phase signals. One or more bit templates at the receiver is correlated with one or more corresponding bit templates in the composite signal received at the receiver to determine where frames start in the composite signal, thereby synchronizing the receiver to the one or more frames in the composite signal.

Abstract: Spread spectrum receiver architectures and methods are described for reducing interference, particularly the interference observed at a user-end terminal in a W-CDMA 3G mobile communications system. Interpath interference which arises due to non-zero cross and auto correlation of more than one spreading code is suppressed by estimating a transmitted signal stream, or a plurality of such signal streams in the case of a plurality of multipath components, respreading this estimated signal and subtracting non-orthogonal interference contributions from a received signal. The techniques provide an improved bit error rate or equivalently, enhanced capacity for a digital mobile communications network.

Abstract: Techniques to iteratively detect and decode data transmitted in a wireless (e.g., MIMO-OFDM) communication system. The iterative detection and decoding is performed by iteratively passing soft (multi-bit) “a priori” information between a detector and a decoder. The detector receives modulation symbols, performs a detection function that is complementary to the symbol mapping performed at the transmitter, and provides soft-decision symbols for transmitted coded bits. “Extrinsic information” in the soft-decision symbols is then decoded by the decoder to provide its extrinsic information, which comprises the a priori information used by the detector in the detection process. The detection and decoding may be iterated a number of times. The soft-decision symbols and the a priori information may be represented using log-likelihood ratios (LLRs).

Abstract: A signal generator and decoder are used for a single sideband spread spectrum signal. A single sideband spread spectrum signal generator and decoder in which single sideband modulation using a complex spreading code is achieved with improved correlation properties, so that the interference between users is reduced.

Abstract: A demodulation circuit for demodulating an FSK signal comprising a long bit having a long bit period and a short bit having a short bit period comprises a bit boundary detection section for detecting a bit boundary timing of each bit, and a bit determination section for making determination for each bit such that a particular bit is determined to be a long bit when a threshold time period has passed during a period from a bit boundary timing at a leading end of the bit to a bit boundary timing at a trailing end of the bit, and a particular bit is determined to be a short bit when the threshold time period has not passed during a period from a bit boundary timing at a leading end of the bit to a bit boundary timing at a trailing end of the bit.

Abstract: A receiver, a system, and an associated method, for receiving a radio signal carrying transmitted data that is subject to distortion in the transmission channel. The receiver includes a plurality of stages that perform parallel interference cancellation (PIC) with respect to a received space-time transmit diversity (STTD) signal to establish successively more accurate estimates of the transmitted data, including a receiver first stage being a RAKE-STTD receiver, a second stage including an minimum mean-square error (LMMSE) equalizer, and preferably a third stage also including an LMMSE. Each stage processes the estimates of the transmitted signal provided by the stage preceding it, as well as the received signal, to mitigate or eliminate as much transmission-channel interference as possible and provide a refined estimate for processing by subsequent stages. Improved channel estimation may be achieved by processing the pilot signal in similar fashion as well.

Abstract: An apparatus comprises a transmitter, a receiver, an antenna and a signal cancellation circuit. The transmitter is configured to send a transmitter signal associated with a frequency. The receiver is associated with the frequency. The antenna is coupled to the transmitter and the receiver. The signal cancellation circuit is coupled to the transmitter, the receiver and the antenna. The signal cancellation circuit is configured to phase shift a first portion of the transmitter signal to produce a phase-shifted signal. The signal cancellation circuit is configured to combine the phase-shifted signal with a second portion of the transmitter signal to produce a combined signal. The second portion of the transmitter signal is associated with a reflection of a third portion of the transmitter signal from the antenna. The first portion, the second portion and the third portion of the transmitter signal are different from each other.

Abstract: A method and apparatus for detecting a channel jammed by narrowband jamming interference in a block oriented digital transmission system such as an orthogonal frequency division multiplexing (OFDM) or discrete multi-tone (DMT) system. A spectrum of a received data bearing signal is examined to identify areas of the spectrum that are likely corrupted by a narrowband jamming interference. The method identifies jammed channels by applying a boxcar filter, in order to identify narrow peaks in the spectrum that are substantially larger in magnitude than adjacent channels. Channels identified as jammed or affected by a jamming signal, are listed in a jam mask used for screening out corrupted channels during data transmission.

Abstract: A method and apparatus for reducing processing requirements of a pool of soft modems is disclosed. In one embodiment, the method comprises queuing one or more retrain requests and responding to the queued retrain requests within a period of time to one or more modems that correspond to the queued retrain requests.

Abstract: A multi-speed jittered signal generator (216, 400) that generates a full-speed jittered signal (404) by scaling a low-speed jittered signal (420) using a frequency scaler (428). The low-speed jittered signal is created by injecting a modulation signal (416) into a reference signal (412) using a jitter injector (432). Injecting jitter into a low-speed reference signal allows the full-speed jittered signal to be of higher quality than conventional jitter signals created by injecting jitter information into a full-speed reference signal. The multi-speed jittered signal generator may be used as part of a testing system (208) for testing various circuitry, such as high-speed serializer/deserializer circuitry (220).

Abstract: A hybrid receiver, and an associated method, for receiving a radio signal carrying transmitted data that is subject to distortion in the transmission channel. The receiver includes a plurality of stages that perform parallel interference cancellation (PIC) to establish successively more accurate estimates of the transmitted data, including a receiver first stage being either a RAKE receiver or a linear minimum mean-square error (LMMSE) receiver, a second stage including an LMMSE, and preferably a third stage also including an LMMSE. Each stage processes the estimates of the transmitted signal provided by the stage preceding it to mitigate or eliminate as much transmission-channel interference as possible and prove a refined estimate for processing by subsequent stages. Improved channel estimation may be achieved by processing the pilot signal in similar fashion as well.

Abstract: A method including searching for a communication channel by activating a receiver having a radio frequency (RF) module and a baseband module for storing a portion of received signals within a first time period, de-activating the RF module of the receiver, and background processing the portion of the received signals with a variable clock rate within a second time period.

Abstract: Fading frequency decision device and method are provided. An inner product value of pilot symbols which are time multiplexed in a control channel which is parallel multiplexed with a data channel, an inner product value of pilot symbols in a channel in which data symbols and pilot symbols are time multiplexed, or an inner product value of pilot symbols of a pilot channel which is parallel multiplexed with a data channel is calculated. A fading frequency is decided based on the calculated inner product value.

Abstract: The invention provides a synchronizer incorporating a ?-? modulator (i.e. a bit stuffing command generator), coupled in series with a frequency offset measurement block and a frequency-locked loop, to synchronize the data rate of an output data stream to that of an input data stream such that jitter energy is shifted up in frequency, simplifying attenuation of the jitter energy when the output data stream is desynchronized (demapped). Placement of the ?-? modulator outside the frequency-locked loop allows selectable adjustment of the frequency offset measurement block's frequency. A mapper incorporating the ?-? modulator interprets the pulse train output by the ?-? modulator as stuff/null/de-stuff commands.

Abstract: An analog signal control method for accurately controlling an analog signal irrespective of a latency. The analog signal control method includes the steps of converting the analog signal to a digital signal, performing an arithmetic processing of the digital signal to generate a control signal for controlling the analog signal, delaying the analog signal corresponding to a latency caused by the generation of the control signal to generate a delayed analog signal, and controlling the delayed analog signal in accordance with the control signal.

Abstract: A user equipment receives a plurality of transmitted data signals in a communication system. The transmitted data signals are received. A channel response is determined for each received data signal. A system response is determined based on in part the channel signals. The system response is expanded to be piecewise orthogonal. Data from the received data signals is retrieved based on in part the expanded system response.

Abstract: Digital signal transmitter devices mostly present a distinct wide-band interference spectrum which renders compliance with the presently applicable EMC standards substantially more difficult. Available provisions for improving the EMC characteristics take an influence on the quality in transmission and on the immunity to interference. By the inventive method the carrier signal or output signal, respectively, of the transmitter is so modulated that the narrow spectral lines are spread and the spectral power density is reduced.

Abstract: A multicode receiver for receiving data carried by a plurality of spread spectrum signals having a corresponding plurality of spreading codes, the spreading codes being substantially mutually orthogonal, the receiver having intercode interference suppression, the receiver including a multicode spread spectrum receiver to provide a set of data estimates having a plurality of estimates of data carried by the plurality of spread spectrum signals, one estimate for each spread spectrum signal, a plurality of respreaders to respread the plurality of data estimates, a plurality of interference suppressers, at least one for each of the plurality of spreading codes, each at least one interference suppresser for each code being configured to suppress respread data estimates for the spread spectrum signals of the other codes, from a received signal, a plurality of rake fingers each having the plurality of interference suppressers, and a plurality of rake combiners, one for each of the plurality of spreading codes.