Abstract: A method and apparatus for decoding baseband OFDM signals include processing that begins by slicing each sub-carrier signal of the OFDM signal into a plurality of error terms. The particular number of error terms generated for each sub-carrier signal depends on the constellation size of the data being carried by each of the sub-carrier signals. The error terms for each sub-carrier signal corresponds to the nearest constellation point having a zero or one in the I or Q direction. The process continues by grouping individual error terms of the plurality of error terms for each sub-carrier signal to produce a plurality of error terms. The processing then continues by de-interleaving each of the plurality of error term groups to produce a corresponding plurality of de-interleaved error term groups.

Abstract: Systems, apparatuses, and methods for low wander timing generation and/or recovery are disclosed here. In one aspect, embodiments of the present disclosure include a communication system for high speed communications between a first location and a second location. The communication system, may include a transmitter module at the first location associated a first clock. The transmitter module may further include a phase detector module that is operable to generate a one or more data bits to indicate phase offset between the first clock and a second clock, the first clock can be associated with a transmission rate and the second clock can be associated with a network link rate and/or a receiver module at the second location associated with the second clock. The receiver module may be coupled to the transmitter module via a network.

Abstract: A digital reception apparatus includes a receiver that performs reception processing on a received signal and an adjuster that adjusts the amplitude of the received signal after the reception processing. A distortion estimator estimates a non-linear distortion of the received signal after the reception processing, the non-linear distortion being caused by the reception processing. A distortion corrector performs a distortion correction on the estimated non-linear distortion. A controller controls the adjuster based on a gain control signal such that the amplitude of a desired signal contained in the received signal after the reception processing and the distortion correction approaches a required level. The distortion estimator estimates the non-linear distortion of the received signal with reference to the gain control signal.

Abstract: A communication system transmits and receives a plurality of spread-spectrum signals having differences in at least one diversity parameter. The signals are highly correlated when their diversity parameters are similar, and the signals are uncorrelated when at least one diversity parameter is different. Any combination of a transmitter, a receiver, and a communication channel may diversity-encode the signals to effect differences in their diversity parameters. A receiver diversity-decoder compensates for differences in a diversity-parameter of at least one received signal to make the signal highly correlated with at least one other received signal. A correlator combines at least two of the received signals to recover an embedded information signal. The communication system enables the use of true-noise signals for spreading information signals, provides simplified receiver designs, and enables antenna arrays to spatially process spread-spectrum signals.

Abstract: An RF receiver which produces quadrature digitized outputs and has a gain control is coupled to a digital gain controller which converts the quadrature digitized outputs into an rms voltage, and iterates over a finite number of steps to quickly control the gain to a level sufficient to achieve subsequent digital signal processing without limitations caused by insufficient dynamic range or nonlinear saturation effects caused by insufficient signal or excessive signal at the A/D input, respectively.

Abstract: A receiver in a data read channel has an input terminal for receiving an input signal provided by a transmitter of the data read channel, and produces an output signal at an output terminal. The receiver includes a finite impulse response (FIR) filter coupled to the input terminal and having filter coefficients capable of being adapted, an interpolated timing-recovery circuit coupled to an output of the FIR filter, the timing-recovery circuit having an output signal coupled to the output terminal of the receiver, and a timer circuit coupled to the output terminal and feedback connected to the timing-recovery circuit, wherein the coefficients of the timing-recovery circuit are dynamically adapted using a cost weighted function through a signal power spectrum of the data read channel.

Abstract: A transmission apparatus includes a frame configuration determiner that determines a modulation system from among a plurality of modulation systems on a communication situation. A first symbol generator modulates a digital transmission signal according to the modulation system determined by the frame configuration determiner and generates a first symbol, the first symbol comprising a first quadrature baseband signal. A second symbol generator modulates the digital transmission signal according to a predetermined modulation system and generates a second symbol, the second symbol comprising a second quadrature baseband signal.

Abstract: The present invention establishes a metric calculation method. A constant calculation circuit 31 calculates constants V/2?A, V/2+A, and A/2, which are required to calculate branch metrics by using an average voltage V/2, corresponding to a parameter R input from an asymmetrical register, which is input from an average voltage register, and output them to adders 33, 35, and 36, respectively. A multiplier 32 multiplies an equalized signal yk by a value P of 1 or ?1 input from a polarity register. A bit shifter 37 shifts by c bits A/2?yk, corresponding to the parameter R input from the asymmetrical register, which is input from the adder 36. That is, the bit shifter 37 multiplies A/2?yk by ?, and outputs it to adders 38 and 39. However, when the parameter R is 0, the bit shifter 37 outputs 0 to the adders 38 and 39. The present invention can be applied to a recording and reproduction apparatus.

Abstract: A system and method are provided for stopping a quantized signal from a noise-shaper with a significantly reduced inband transient, compared to a traditional random stop of a noise-shaped signal. The noise-shaped signal is stopped at a favorable time controlled by a detector that monitors the noise-shaped signal. The detector indicates the occurrence of a good time to stop the noise-shaper such that the transient due to the stop is minimized in a fashion that substantially reduces the inband disturbance.

Abstract: A new method makes the most efficient use of the scarce spectral bandwidth in a wireless discrete multitone spread spectrum communications system by updating the spectral and/or spatial spreading weights at a rate that is determined by the measured quality of the link. Low quality links require more frequent updates of the spreading weights than do higher quality links. Spreading weights and despreading weights for a station are adaptively updated, depending on the error in received signals. If the error value is less than a threshold error value, then the method maintains the existing spreading weights as the current spreading weights to apply to an outgoing data signal. Alternately, if the error value is greater than the threshold error value, then the method adaptively calculates updated despreading weights at the base station from the first spread signal and calculates updated spreading weights as the current spreading weights from the updated despreading weights to apply to the outgoing data signal.

Abstract: An apparatus and method for detecting a power ratio between a traffic channel and a pilot channel in a mobile communication system. The apparatus is operable to generate a second signal by performing channel estimation using a second channel signal, and generate a first signal by channel-compensating the first channel signal using the second signal. The apparatus is further operable to generate absolute values of symbols constituting the first signal, select absolute values in a predetermined length after sorting the absolute values in magnitude order, calculate an average value of the selected absolute values, calculate a square of an absolute value of the second signal, and generate the power ratio using a ratio of the average value to the square of the absolute value of the second signal.

Abstract: In a method and apparatus for communicating data, a decision feedback equalizer equalizes received data to reduce channel related distortion in the received data. An extracted clock signal is generated from the equalized data. The phase of the extracted clock signal may be adjusted to compensate for processing delay during equalization of the received data. The extracted clock signal may be used to clock a retimer of the decision feedback equalizer to generate recovered data.

Abstract: An OFDM receiving device for adjusting a beam formation azimuth through a plurality of antennas, a communication device using the same, and a method thereof.

Abstract: The present invention facilitates clock and data recovery (330,716/718) for serial data streams (317,715) by providing a mechanism that can be employed to maintain a fixed tracking capability of an interpolator based CDR circuit (300,700) at multiple data rates (e.g., 800). The present invention further provides a wide data rate range CDR circuit (300,700), yet uses an interpolator design optimized for a fixed frequency. The invention employs a rate programmable divider circuit (606,656,706) that operates over a wide range of clock and data rates (e.g., 800) to provide various phase correction step sizes (e.g., 800) at a fixed VCO clock frequency. The divider (606,656,706) and a finite state machine (FSM) (612,662,712) of the exemplary CDR circuit (600,650,700) are manually programmed based on the data rate (614,667).

Abstract: A method is provided for initiating communications over a channel between a transmitter and a receiver within a specified spectral range, subject to a mask to be applied at the transmitter so as to attenuate at least one segment of the spectral range. The method includes providing to the receiver a definition of the at least one segment and of a level of attenuation to be applied within the at least one segment during a training interval of the communications. A training signal is transmitted from the transmitter to the receiver while applying to the training signal the level of attenuation within the at least one segment. The receiver compensates for a response of the channel based on the received training signal and on the definition of the at least one segment and of the level of attenuation.

Abstract: A raking receiver is provided in a wireless network. The raking receiver includes an antenna, first through Nth wavelet forming networks, first through Nth weighting mixers, a summer, a path mixer, and a signal processing circuit. The antenna receives an incoming signal. The first through Nth wavelet forming networks produce first through Nth locally generated wavelets. The first through Nth weighting mixers multiply the first through Nth locally generated wavelets by first through Nth weighting values, respectively, to produce first through Nth weighted wavelets. The summer adds together the first through Nth weighted wavelets to produce a weighted correlation input signal. The path mixer multiplies the incoming signal with the weighted correlation input signal to produce a correlated signal. And the signal processing circuit receives the correlated signal and produces a digital bit value. N is preferably an integer greater than 1.

Abstract: An apparatus and method for transmitting and receiving data, wherein retransmissions of information can be a different size from the initial transmission. The invention utilizes a partial Chase encoder 306 to truncate or expand data depending on the availability of channel resources for retransmission. A partial Chase combiner 314 processes the received demodulated data based solely on the number of codes and modulation received (i.e., predetermined, with no additional signaling required). If the received retransmission is smaller than the first transmission, only a portion of the soft bits are combined. If the retransmission is larger than the first transmission, some values of the stored first transmission are combined with more than one received soft bit in the retransmission.

Abstract: In a communication system, a method and an accompanying apparatus determine a number of available fingers (110A-N) in a receiver (100). A controller (121) adjusts a threshold based on the determined number of the available fingers (110). The adjusted threshold may be one of, or any combination of, a pilot signal search threshold, a lock/unlock threshold, and a combine/un-combine threshold. The number of available fingers (110) may change after the threshold is adjusted.

Abstract: In a method and apparatus for enabling fast clock phase locking in a phase-locked loop, a sampling clock generator generates sampling clock signals in response to an oscillator output of the phase-locked loop. A detector unit samples an input digital signal to the phase-locked loop at clock edges of the sampling clock signals to obtain multiple sampling points of the input digital signal, and compares logic levels of each temporally adjacent pair of the sampling points to detect presence of a logic level transition in the input digital signal. A selector unit is controlled by the detector unit to select one of the sampling clock signals, which has one of the clock edges thereof defining an interval that was detected to have occurrence of the logic level transition in the input digital signal, and which is subsequently provided to the phase-locked loop as an input phase-locking clock signal.

Abstract: A circuit and method for correcting phase of a received phase modulated (PM) signal. The method uses k most recently received data bits, which alternate between in-phase I and quadrature Q bits, as an address for a lookup table 60. The lookup table outputs a phase figure 62 derived from a reconstructed waveform. When the most recent k bit is a Q bit, the complement 68 of the phase figure 62 is calculated to yield a phase correction. Otherwise, the phase figure is the phase correction, which is applied to adjust the phase of a delayed version of the received signal. The delayed, phase adjusted signal is then applied to correct the phase of a received signal. The circuit splits an input PM signal in parallel between a matched filter 54 and a delay block 76, 88. The matched filter output provides the input to a register 58 for storing the k data bits. The delay block holds the PM signal until it is input into a loop phase shifter 78 synchronously with the phase correction.