Abstract: A control signal receiver includes a converting circuit and a synchronization detection circuit. The converting circuit generates a complex control symbol stream including transmission configurations by converting an input signal. The synchronization detection circuit generates a first bit stream by applying a first determination criterion to the complex control symbol stream and generates a first synchronization signal by comparing the first bit stream with a reference synchronization word. The synchronization detection circuit generates a second bit stream by applying the first determination criterion and a second determination criterion to the complex control symbol stream in that order and generates a second synchronization signal by comparing the second bit stream with the reference synchronization word. The synchronization detection circuit outputs one of the first synchronization signal and the second synchronization signal as asynchronization enable signal.

Abstract: In one aspect, an orthogonal frequency division multiplexing (OFDM) receiver includes an offset compensator, a fast Fourier transform (FFT) block, a control unit, a channel impulse response estimation block, and a sampling offset estimation block. The offset compensator is configured to receive a digital input signal and a sampling offset, and to convert the digital input signal into a baseband signal in accordance with the sampling offset. The fast Fourier transform (FFT) block is configured to perform an FFT operation of the base band signal output from the offset compensator and to output a corresponding FFT result. The control unit is configured to generate OFDM symbol information and a plurality of control signals based on the FFT result. The channel impulse response estimation block is configured to periodically generate receiving channel impulse response information of a receiving channel based on the FFT result.

Abstract: A sampling offset estimation apparatus including a pilot sub-carrier refiner, an information sub-carrier refiner, a data sub-carrier refiner, and a sampling offset estimator. The pilot sub-carrier refiner to refine a pilot sub-carrier extracted from a differential demodulated signal, and to generate a reference pilot sub-carrier. The information sub-carrier refiner to refine an information sub-carrier extracted from the differential demodulated signal, and to generate a reference information sub-carrier. The data sub-carrier refiner to refine a data sub-carrier extracted from the differential demodulated signal, and to generate a reference data sub-carrier. The sampling offset estimator to estimate a sampling offset included in the differential demodulated signal, on a basis of the reference pilot sub-carrier, the reference information sub-carrier, and the reference data sub-carrier.

Abstract: An equalizing apparatus for an orthogonal frequency division multiplexing (OFDM) wireless communication receiving system includes a channel estimation block, a first equalizer, and an error compensation block. The channel estimation block performs channel estimation by extracting a pilot signal from a signal supplied to the first equalizer. The first equalizer performs first channel equalization based on the channel estimation from the channel estimation block. The error compensation block outputs an error compensation value of the first equalizer, based on data signals from the first equalizer. The error compensation value may be used by the first equalizer and/or a second equalizer. Related methods and computer program products are also described.

Abstract: A demodulator recovers a transmitted symbol represented by a received quadrature amplitude modulation (QAM) signal. Such a demodulator may include: a QAM-decoding block operable to map a received signal vector onto a constellation so as to yield a first symbol, and identify a next-most probable second symbol based upon the signal vector; and a selection unit operable to select, among the first and second symbols, the one having the lower error content as corresponding to the transmitted symbol. A corresponding method may include similar steps.

Abstract: There is provided a multi sub-carrier communication system for providing improved performance of a frequency equalizer and a method thereof. The multi sub-carrier communication system includes a frequency equalization coefficient (vector) calculation unit that receives an equalized signal outputted from a frequency equalizer and periodically calculates a new frequency equalizer coefficient (vector) which is used to update the frequency equalizer coefficient (vector) used by the frequency equalizer. The multi sub-carrier communication system periodically updates the frequency equalization coefficient (vector) (after an initialization interval for initially estimating a channel characteristic) by periodically calculating the frequency equalization coefficient (vector) during a data receiving interval and thus, it is possible to dynamically adapt to changes of the channel characteristic over the passage of time, thereby improving performance of the frequency equalizer.

Abstract: In one aspect, an orthogonal frequency division multiplexing (OFDM) receiver includes an offset compensator, a fast Fourier transform (FFT) block, a control unit, a channel impulse response estimation block, and a sampling offset estimation block. The offset compensator is configured to receive a digital input signal and a sampling offset, and to convert the digital input signal into a baseband signal in accordance with the sampling offset. The fast Fourier transform (FFT) block is configured to perform an FFT operation of the base band signal output from the offset compensator and to output a corresponding FFT result. The control unit is configured to generate OFDM symbol information and a plurality of control signals based on the FFT result. The channel impulse response estimation block is configured to periodically generate receiving channel impulse response information of a receiving channel based on the FFT result.

Abstract: An asymmetrical digital subscriber line (ADSL) communication system enhances the signal-to-noise ratio (SNR) of the received signals by conducting a PLL process with a tone conditioned on the most superior SNR, instead of a fixed tone. An improvement in data rate is thereby achieved.

Abstract: A sampling offset estimation apparatus including a pilot sub-carrier refiner, an information sub-carrier refiner, a data sub-carrier refiner, and a sampling offset estimator. The pilot sub-carrier refiner to refine a pilot sub-carrier extracted from a differential demodulated signal, and to generate a reference pilot sub-carrier. The information sub-carrier refiner to refine an information sub-carrier extracted from the differential demodulated signal, and to generate a reference information sub-carrier. The data sub-carrier refiner to refine a data sub-carrier extracted from the differential demodulated signal, and to generate a reference data sub-carrier. The sampling offset estimator to estimate a sampling offset included in the differential demodulated signal, on a basis of the reference pilot sub-carrier, the reference information sub-carrier, and the reference data sub-carrier.

Abstract: A receiving device of a multiple communications channel system includes: a noise detector that detects channel noise among the received data signals and selects at least one channel among a plurality of channels in the multiple channel communications system on which the received data signals are largely unaffected by noise; a magnitude checker that selects at least one channel among the plurality of channels on which the received data signals have a magnitude greater than a predetermined magnitude among the received data; a QAM unit constellation detector that detects a QAM unit constellation using a reference constellation from a constellation value on a QAM coordinate plane of the selected signal channel; and a constellation rotation unit that rotates and maps the detected QAM unit constellation value onto a Real=Imaginary axis.

Abstract: A wireless terminal reliably supplies battery power to a wireless terminal body, and reduces the number of fabrication processes and fabrication cost. The battery contact system of the wireless terminal includes a body having a printed circuit board, a battery compartment, a battery detachably accommodated in the battery compartment, and at least one connection unit for transmitting battery power the body. The connection unit is an insulated elastic body protruding from the battery compartment and encompassing flexible conductors within the insulated elastic body.

Abstract: An equalizing apparatus for an orthogonal frequency division multiplexing (OFDM) wireless communication receiving system includes a channel estimation block, a first equalizer, and an error compensation block. The channel estimation block performs channel estimation by extracting a pilot signal from a signal supplied to the first equalizer. The first equalizer performs first channel equalization based on the channel estimation from the channel estimation block. The error compensation block outputs an error compensation value of the first equalizer, based on data signals from the first equalizer. The error compensation value may be used by the first equalizer and/or a second equalizer. Related methods and computer program products are also described.

Abstract: A digital subscriber line (DSL) receiver includes a discrete multitone (DMT) receiver circuit operative to receive a DSL signal and to generate signal samples corresponding to respective frequency division multiplexed tones of the DSL signal. The receiver further includes a synchronization circuit operative to determine phase information for a crosstalk source indication signal, e.g., an integrated services digital network (ISDN) timing reference indication signal, carried by one of the plurality of frequency-division multiplexed tones from the signal samples generated by the DMT receiver circuit and to determine frame timing for the DSL signal responsive to the determined phase information. The DMT receiver circuit may include a buffer operative to receive and store samples of the DSL signal, and a fast Fourier transformer (EFT) operative to generate the signal samples for the respective ones of the plurality of frequency-division multiplexed tones from the stored samples of the DSL signal.

Abstract: There is provided a multi sub-carrier communication system for providing improved performance of a frequency equalizer and a method thereof. The multi sub-carrier communication system includes a frequency equalization coefficient (vector) calculation unit that receives an equalized signal outputted from a frequency equalizer and periodically calculates a new frequency equalizer coefficient (vector) which is used to update the frequency equalizer coefficient (vector) used by the frequency equalizer. The multi sub-carrier communication system periodically updates the frequency equalization coefficient (vector) (after an initialization interval for initially estimating a channel characteristic) by periodically calculating the frequency equalization coefficient (vector) during a data receiving interval and thus, it is possible to dynamically adapt to changes of the channel characteristic over the passage of time, thereby improving performance of the frequency equalizer.

Abstract: Disclosed is a wireless terminal capable of reliably supplying battery power to a wireless terminal body, and capable of reducing the number of fabrication processes and fabrication costs. The battery contact system of a wireless terminal comprises: a body having a printed circuit board; a battery compartment on one surface thereof; a battery detachably accommodated in the battery compartment; and a connection unit for transmitting battery power the body, wherein the connection unit comprises an insulated elastic body protruding from the battery compartment for elastically connecting to the battery and flexible conductors within the insulated elastic body in contact with the battery terminals and a connection portion of the printed circuit board.

Abstract: A receiving device of a multiple communications channel system includes: a noise detector that detects channel noise among the received data signals and selects at least one channel among a plurality of channels in the multiple channel communications system on which the received data signals are largely unaffected by noise; a magnitude checker that selects at least one channel among the plurality of channels on which the received data signals have a magnitude greater than a predetermined magnitude among the received data; a QAM unit constellation detector that detects a QAM unit constellation using a reference constellation from a constellation value on a QAM coordinate plane of the selected signal channel; and a constellation rotation unit that rotates and maps the detected QAM unit constellation value onto a Real=Imaginary axis.

Abstract: A demodulator recovers a transmitted symbol represented by a received quadrature amplitude modulation (QAM) signal. Such a demodulator may include: a QAM-decoding block operable to map a received signal vector onto a constellation so as to yield a first symbol, and identify a next-most probable second symbol based upon the signal vector; and a selection unit operable to select, among the first and second symbols, the one having the lower error content as corresponding to the transmitted symbol. A corresponding method may include similar steps.

Abstract: An asymmetrical digital subscriber line (ADSL) communication system enhances the signal-to-noise ratio (SNR) of the received signals by conducting a PLL process with a tone conditioned on the most superior SNR, instead of a fixed tone. An improvement in data rate is thereby achieved.

Abstract: A digital subscriber line (DSL) receiver includes a discrete multitone (DMT) receiver circuit operative to receive a DSL signal and to generate signal samples corresponding to respective frequency division multiplexed tones of the DSL signal. The receiver further includes a synchronization circuit operative to determine phase information for a crosstalk source indication signal, e.g., an integrated services digital network (ISDN) timing reference indication signal, carried by one of the plurality of frequency-division multiplexed tones from the signal samples generated by the DMT receiver circuit and to determine frame timing for the DSL signal responsive to the determined phase information. The DMT receiver circuit may include a buffer operative to receive and store samples of the DSL signal, and a fast Fourier transformer (FFT) operative to generate the signal samples for the respective ones of the plurality of frequency-division multiplexed tones from the stored samples of the DSL signal.