Abstract: A receiver includes a channel length determination unit to determine a channel length for use by a channel estimator. In at least one embodiment, an iterative process is used to find a channel length (or a combination of channel length and one or more other channel related parameters) that optimizes a channel estimation quality criterion. A time tracking method is also provided that uses an early metric, a center metric, and a late metric to determine an appropriate timing.

Abstract: A novel technique and structure that maximizes the extraction of information from reference pulses for UWB-TR receivers is introduced. The scheme efficiently processes an incoming signal to suppress different types of UWB as well as non-UWB interference prior to signal detection. Such a method and system adds a feedback loop mechanism to enhance the signal-to-noise ratio of reference pulses in a conventional TR receiver. Moreover, sampling the second order statistical function such as, for example, the autocorrelation function (ACF) of the received signal and matching it to the ACF samples of the original pulses for each transmitted bit provides a more robust UWB communications method and system in the presence of channel distortions.

Abstract: Characterizing channel response in a single upstream burst using redundant information from training tones (TTs). The invention is operable to utilize inserted TTs, contained within a transmitted data frame, to provide for an improved estimate of a communication channel's actual response and an improved estimate of the noise of the communication channel. The invention determines a maximum allowable delay spread of the many communication paths within a multi-path communication channel. Using the redundant TTs information then a portion of the finite impulse response of the communication channel, within the time domain, may be zeroed, thereby providing a much improved channel estimate and noise estimate. Using the redundant TTs, less noise is introduced onto the data tones (DTs) within a data frame. The present invention is also able to identify those portions of the TTs that are attributable to the actual channel and those that are attributable to the channel's noise.

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: A robust and flexible system for signal parameter measurements in the field of signal processing dynamically uses signal parameters from previous signal detections and parametric priorities to adaptively control and process the signal in an efficient and reliable manner. The system provides for improved fine grain signal parameter measurements through the use of adaptive arbitration to control signal processing. The system improves measurement accuracy for various signal characteristics including pulse width, amplitude, frequency and timing information. The system also provides signal parameter measurements while requiring less power, size, and weight than conventional systems.

Abstract: In a digital receiver for receiving COFDM modulated television signals or the like, consecutive samples are compared with a detection threshold and the number of samples having amplitudes greater than the threshold is determined. This is compared with a further threshold and, if the number of such samples exceeds the further threshold, affected samples are blanked to zero. Similarly, an automatic gain control loop is disabled when the samples are blanked. A demodulator forms the difference in phase of pilot carriers from symbol to symbol. If the variance of the phase differences exceeds an averaged value, this indicates the presence of impulsive noise and is used to inhibit signal correction techniques within the demodulator. Noise energy is thus reduced and propagation of effects resulting from impulsive noise from symbol to symbol is substantially reduced.

Abstract: In an exemplary embodiment, a multi-rate data conversion circuit receives digital data at varying data rates, receives a data rate input corresponding to the digital data and converts the digital data to a converted output based upon the data rate input. A direct digital synthesis circuit receives the converted output and synthesizes a modulated output signal based upon the converted output. A multi-rate converter receives the digital data, the data rate input and a clock signal and converts the digital data to converted digital data. A multi-rate digital data filter receives the converted digital data and produces a filtered digital output. An output scaler receives the filtered digital output and produces a scaled and filtered digital output. Finally, an adder combines the scaled and filtered digital output with a center frequency input and produces the converted output.

Abstract: A method of compressing sounds in mobile terminals according to the present invention transforms pulse code modulations (PCM) codes, which are source data of bell sounds using recorded sounds or voice memos and are generated by sampling the sounds, through applying a differential method and, then, compresses the PCM codes using Lempel Ziv Welch (LZW) compresses technique, thus reducing a storage space required for storing bell sounds using sounds or voice memos in mobile terminals. According to the present invention, compression efficiency is maximized upon using LZW algorithm by transforming PCM code through applying differential method, thereby increasing restoration efficiency of original sounds and heightening compression efficiency by about 50%, compared with the existing compression storage method using ADPCM.

Abstract: This disclosure is generally directed to communication systems, devices used in communication systems and associated methods which may implement parallel hypothesis search techniques. The disclosed parallel hypothesis search techniques may permit a hypothesis to be dismissed early (i.e., before hypotheses in other searchers have completed their evaluation). Early hypothesis dismissal permits a new hypothesis to be loaded into the searcher while other searchers advantageously continue to evaluate their hypotheses.

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 method for facilitating broadband multi-carrier wireless transmission, whereby a plurality of transmit antennas are divided into two or more transmit antenna groups of transmit antennas so that the correlation between antennas in each group is minimized, and each group of antennas transmits on a predetermined frequency with a different time periodicity, and each transmit antenna in each group transmits training sequences which are reciprocally time-orthogonal. Each of a plurality of receive antennas receives signals from each transmit antenna group. The signals from each group are separated via a band-pass filter, and a maximum estimation range of a frequency offset estimation algorithm is determined by the group having the shortest time period, and the accuracy of the frequency offset estimation algorithm is determined by the group having the longest time period. The received signal is corrected with the frequency offset.

Abstract: A communication system is disclosed that allows high data-rate transmission of data between components. N-bit parallel data is transmitted in K-frequency separated channels on the transmission medium so as to fully take advantage of the overall bandwidth of the transmission medium. As a result, a very high data-rate transmission can be accomplished with low data-bit transmission on individual channels.

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: The phase and frequency comparator for controlling, as a function of the frequency (Fref) and the phase of a reference signal (Sref), the frequency (Fvco) and the phase of the output signal of a controlled-frequency oscillator comprises means (11, 12, 21, 22) for detecting in the reference signal (Sref) and in the signal from the oscillator events representative of the frequency and the phase of that signal, means (S1+, S1, 16, 17) for generating a first or second signal on the detection of an event, means (S2+, S2?, 24 to 27) for generating a third or fourth signal on the detection of an event, if the first or second signal, respectively, is generated, means for applying all of the signals (Io; Vo) generated to the oscillator, and means (13, 23) for halting the generation of the first and second signals or of all of the signals if the first and second signals or the third and fourth signals, respectively, are generated simultaneously.

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.

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: The phase of a data signal relative to a reference clock signal is approximated relatively accurately using only relatively coarse increments of phase shift between trial version of a sampling clock signal (derived from the reference clock signal). Information about which amounts of progressively greater phase shift in the sampling clock signal cause loss of alignment between a training pattern and training data in the data signal can be used for such purposes as identifying the amount of phase of shift of the reference clock signal that will be best for use in sampling the data signal during normal (post-training) operation.

Abstract: A technique of decoding a biphase signal comprises sampling the biphase signal to obtain phase sample values and sampling the biphase signal to obtain magnitude sample values. A first digital signal is derived from the phase sample values and associated bit combinations are formed from the first digital signal. A decision is made whether the bit combination is an erroneous bit combination, and a probability check is performed to obtain probability values that decide which parts of the erroneous bit combination are true and which are false. A corrected bit combination is generated from the obtained probability values, and a second digital signal is generated whose data states are formed from the valid bit combination and, in the presence of an erroneous bit combination, from the corrected bit combination.

Abstract: A system and method that scrambles the phase characteristic of a carrier signal are described. The scrambling of the phase characteristic of each carrier signal includes associating a value with each carrier signal and computing a phase shift for each carrier signal based on the value associated with that carrier signal. The value is determined independently of any input bit value carried by that carrier signal. The phase shift computed for each carrier signal is combined with the phase characteristic of that carrier signal so as to substantially scramble the phase characteristic of the carrier signals. Bits of an input signal are modulated onto the carrier signals having the substantially scrambled phase characteristic to produce a transmission signal with a reduced PAR.