Abstract: Provided is a horse-riding bicycle in which a horse-riding effect is obtained by performing both normal driving and horse-riding driving (swinging driving), a user is allowed to simply switch a driving mode between a normal driving mode and a horse-riding driving mode, and a horse-riding driving structure is improved to have a simple structure so that a reduction in costs is achieved and, further, a switching operation between the normal driving mode and the horse-riding driving mode is smoothly performed.

Abstract: Disclosed are a method and apparatus for processing a transmission signal using a window function that changes a spectrum characteristic of a symbol. A transmission apparatus includes a symbol generator that generate a plurality of consecutive symbols, and a symbol windowing processor that is coupled with the symbol generator. The symbol windowing processor applies a first window function and a third window function that uses a difference between the first window and a second window, and changes a spectrum characteristic of each of the plurality of consecutive symbols, and processes neighboring symbols from among the plurality of consecutive symbols of which spectrum characteristics are changed, such that the symbols partially overlap one another.

Abstract: The present invention provides a modulo operation method. The modulo operation method, in a case where the square of a divisor N is greater than or equal to a dividend C, includes: determining the number of computation stages n satisfying 2n<N?2n+1; performing an initialization operation by initializing a constant a to the smallest integer greater than or equal to half of N; performing a first operation by subtracting, when C is greater than or equal to N·a (product of N and a), the value of C by the value of N·a; and performing a second operation by assigning the smallest integer greater than or equal to half of a to the value of a, wherein the value of C is output as the result of modulo operation after the first operation and the second operation are repeated n times. In the first operation, when C is less than N·a, the value of C is unchanged.

Abstract: A smoothing apparatus for peak windowing includes an operator for generating a first input signal for smoothing using an input signal for peak windowing and a predetermined clipping threshold level. The apparatus also includes a subtractor for subtracting a feedback signal from the first input signal, and a maximum operator for generating a second input signal. The apparatus also includes a feedback path for generating a feedback signal for a next smoothed input signal by multiplying samples of the second input signal by window coefficients in a first window coefficient combination and a predetermined gain and summing up the multiplication results. The apparatus further includes a convolutional operator for generating a smoothed signal by multiplying samples of the second input signal by window coefficients in a second window coefficient combination for low pass filtering and summing up the multiplication results.

Abstract: An apparatus and a method for processing reduced bandwidth Envelope Tracking (ET) and Digital Pre-Distortion (DPD) are provided. The apparatus includes a Crest Factor Reduction (CFR) unit, a resealing Digital Pre-Distortion (DPD) unit, an envelope converter, a Supply Modulator (SM), and a Power Amplifier (PA). The CFR unit suppresses an increase of a side lobe occurring when a Peak to Average Power Ratio (PAPR) decreases with respect to a signal generated in a baseband according to a standard and passes through a transmit (Tx) filter. The resealing DPD unit receives an original envelope amplitude and a reduced bandwidth envelope amplitude of an In-phase/Quadrature-phase (I/Q) signal output from the CFR unit to perform a pre-distortion process. The envelope converter converts an envelope signal to a reduced bandwidth envelope signal based on the I/Q signal output from the CFR unit.

Abstract: A method and apparatus for reducing a Peak to Average Power Ratio (PAPR) using peak windowing is provided. In the apparatus, an absolute value calculator calculates an absolute value of an input signal, a subtractor subtracts a predetermined clipping threshold level from the absolute value, a smoothing unit performs smoothing on the subtracted signal according to a predetermined smoothing scheme and outputs a first smoothed signal, an adder adds the first smoothed signal to the clipping threshold level, an inverse calculator outputs a second smoothed signal by multiplying the clipping threshold level by an inverse of the added signal, and a multiplier outputs a final PAPR-reduced signal by multiplying the input signal by the second smoothed signal.

Abstract: A method and apparatus for transmitting a signal whereby it is determined if a Bandwidth Expansion Factor (BEF) Q is an integer, the BEF being determined as N/M according to a number N of subcarriers of a system band and a number M of subcarriers of an allocated band, an input signal to be transmitted Q times in a time domain when the Q is an integer is expanded, a Single Carrier Frequency Division Multiplexing Access (SC-FDMA) signal is generated, and the SC-FDMA signal is transmitted.

Abstract: A method and an apparatus for reducing Digital-to-Analog Conversion (DAC) bits at a transmitter of a Frequency Division Multiple Access (FDMA) system reduces a number of the bits for conversion so as to save power and reduce the cost of operation. The method can include generating a digital signal gain control value and an analog signal gain control value using subcarrier allocation information, a required Signal to Noise Ratio (SNR), and a Peak to Average Power Ratio (PAPR); controlling a gain of a signal input to a digital-to-analog converter using the digital signal gain control value; converting a digital signal of the controlled gain to an analog signal using the digital-to-analog converter; and restoring an original signal by controlling a gain of a signal output from the digital-to-analog converter using the analog signal gain control value.

Abstract: The present invention provides a modulo operation method. The modulo operation method, in a case where the square of a divisor N is greater than or equal to a dividend C, includes: determining the number of computation stages n satisfying 2n<N?2n+1; performing an initialization operation by initializing a constant a to the smallest integer greater than or equal to half of N; performing a first operation by subtracting, when C is greater than or equal to N·a (product of N and a), the value of C by the value of N·a; and performing a second operation by assigning the smallest integer greater than or equal to half of a to the value of a, wherein the value of C is output as the result of modulo operation after the first operation and the second operation are repeated n times. In the first operation, when C is less than N·a, the value of C is unchanged.

Abstract: A smoothing apparatus for peak windowing includes an operator for generating a first input signal for smoothing using an input signal for peak windowing and a predetermined clipping threshold level. The apparatus also includes a subtractor for subtracting a feedback signal from the first input signal, and a maximum operator for generating a second input signal. The apparatus also includes a feedback path for generating a feedback signal for a next smoothed input signal by multiplying samples of the second input signal by window coefficients in a first window coefficient combination and a predetermined gain and summing up the multiplication results. The apparatus further includes a convolutional operator for generating a smoothed signal by multiplying samples of the second input signal by window coefficients in a second window coefficient combination for low pass filtering and summing up the multiplication results.

Abstract: A method and apparatus for reducing a Peak to Average Power Ratio (PAPR) using peak windowing is provided. In the apparatus, an absolute value calculator calculates an absolute value of an input signal, a subtractor subtracts a predetermined clipping threshold level from the absolute value, a smoothing unit performs smoothing on the subtracted signal according to a predetermined smoothing scheme and outputs a first smoothed signal, an adder adds the first smoothed signal to the clipping threshold level, an inverse calculator outputs a second smoothed signal by multiplying the clipping threshold level by an inverse of the added signal, and a multiplier outputs a final PAPR-reduced signal by multiplying the input signal by the second smoothed signal.

Abstract: A method and apparatus for transmitting a signal in a Single Carrier-Frequency Division Multiplexing Access (SC-FDMA) communication system are provided. The method includes determining if a Bandwidth Expansion Factor (BEF) Q is an integer, the BEF being determined as N/M according to a number N of subcarriers of a system band and a number M of subcarriers of an allocated band, expanding an input signal to be transmitted Q times in a time domain when the Q is an integer, generating an SC-FDMA signal, and transmitting the SC-FDMA signal.

Abstract: A method and an apparatus for reducing Digital-to-Analog Conversion (DAC) bits at a transmitter of a Frequency Division Multiple Access (FDMA) system reduces a number of the bits for conversion so as to save power and reduce the cost of operation. The method can include generating a digital signal gain control value and an analog signal gain control value using subcarrier allocation information, a required Signal to Noise Ratio (SNR), and a Peak to Average Power Ratio (PAPR); controlling a gain of a signal input to a digital-to-analog converter using the digital signal gain control value; converting a digital signal of the controlled gain to an analog signal using the digital-to-analog converter; and restoring an original signal by controlling a gain of a signal output from the digital-to-analog converter using the analog signal gain control value.

Abstract: A method and apparatus for block interleaving that eliminates the step of intermediary buffering. The method includes: (a) calculating a memory address at which first output data, of which number is equal to the number of rows of a first encoder is stored, (b) storing the first output data at the calculated memory address of a circular buffer, (c) storing second output data at an address which is incremented by a specific constant value from the calculated memory address of the circular buffer, and (d) storing (n+1)th output data at an address which is incremented by n from the calculated memory address of the circular buffer.