Abstract: A digital RF receiver does not use a separate receiver according to a mode and a band for multi-mode reception, MIMO reception, and bandwidth extension reception, and changes only setting variables in a single receiver structure so as to implement multi-mode reception, MIMO reception, bandwidth extension reception, and/or simultaneous multi-mode operation, such that complexity of the receiver, development cost, and power consumption can be reduced.

Abstract: The present invention relates to a single frequency synthesizer based FDD transceiver. A single frequency synthesizer generates and provides a carrier frequency so that frequency up-conversion and frequency down-conversion can be performed at the time of transmission and reception. Accordingly, the area, power consumption, and design complexity of the entire system can be reduced, and the performance of the system can be improved.

Abstract: An embodiment of the present invention relates to a radar apparatus, wherein a distance to a target and a velocity of the target are measured by transmitting a digitally modulated transmitting signal using a digital code and receiving and demodulating an echo signal returned due to reflection of the transmitting signal from the target.

Abstract: This invention is regarding mobile communication digital receiver and operating methods of a digital front end, which uses a digital mixer to change the center frequency to DC; a digital mixer allows the user to evade I/Q mismatch challenges; an Analog-to-Digital Converter (ADC) converts a Radio Frequency analog signal to a digital signal; a digital mixer converts the ADC's output signal's center frequency to DC; a digital front end has an automatic gain control over multiple frequency bands and contains a noise filter; a modem receives the digital front end's output and demodulates the signal.

Abstract: Disclosed is a method for receiving an analog signal from a receiver supporting at least a first channel band and a second channel band. The method for receiving an analog signal includes sampling the analog signal received through an antenna, generating a decimated signal by passing the sampled signal to a CIC decimation filter; and inputting the decimated signal to a channel selection filter.

Abstract: Provided are a multiplierless FIR digital filter and a method of designing the same, in which a filtering operation is performed by a small addition/subtraction circuit using extracted information after analyzing the property of a given coefficient and extracting information required for design by only adding/subtracting operations. In the method of designing the multiplierless FIR digital filter, tables are created to extract and store information needed for adding and subtracting operations. An addition table is created to store values obtained by adding the input data synchronized with a clock frequency. Further, a value corresponding to multiplication is obtained by performing extraction and error correction on the added values from the tables, and an adder chain of an output terminal sums up the values and outputs the filtering results, thereby effectively implementing a logic circuit of the multipliedess FIR digital filter.

Abstract: A method for stable channel estimation to increase frequency band efficiency that is lost by using a pilot, and to reduce the complexity and the sensitivity to channel zero. The method includes generating an i-th symbol block Si including N carriers, performing an inverse fast Fourier transform (IFFT) operation on the i-th symbol block, and forming an orthogonal frequency division multiplexing (OFDM) symbol block. The method also includes attaching a guard interval sample in front of the i-th OFDM symbol block Ui and forming at least one OFDM symbol block Ui,cp. The method further includes modeling the formed OFDM symbol block Ui,cp with a channel finite impulse response (FIR) filter and estimating channel impulse response using signals yi received through a channel.

Abstract: A waveform interpolation speech coding apparatus and method for reducing complexity thereof are disclosed. The waveform interpolation speech coding apparatus includes: a waveform interpolation encoding unit for receiving a speech signal, calculating parameters for a waveform interpolation from the received speech signal, and quantizing the calculating parameters; and a realignment parameter calculating unit for restoring a characteristic waveform (CW) using the quantized parameter, calculating a realignment parameter that maximizes a cross-correlation among consecutive CWs for the restored CW.

Abstract: Provided is a method for converting a dimension of a vector. The vector dimension conversion method for vector quantization includes the steps of: extracting a specific parameter having a pitch period from an input speech signal and then generating a vector of a dimension that varies according to the pitch period; dividing an entire frequency domain of the generated vector of the variable dimension into at least two frequency domains; and converting the vector of the variable dimension into vectors of mutually different fixed dimensions according to the divided frequency domains. Thereby, not only an error due to the vector dimension conversion is suppressed but codebook memory required for the vector quantization is effectively reduced.

Abstract: Provided is a receiver of a multi-input multi-output system using multiple antennas, the receiver including: a first multiplying unit for multiplying a vector r received via the antenna by a Hermitian matrix Q; a candidate transmitting vector generating unit for detecting a signal on a lowest modulation order transmitting antenna from the received vector y output from the first multiplying unit, creating as many symbol candidates as the modulation order of the detected signal, and generating a candidate transmitting vector using each symbol candidate; a transmitting vector determining unit for obtaining a distance between each candidate transmitting vector generated by the candidate transmitting vector generating unit and the received vector y to determine a final transmitting vector; and a demodulating unit for demodulating the final transmitting vector determined by the transmitting vector determining unit.

Abstract: Provided is a transmitter for a multi-input multi-output system including: a memory for storing a modulation system and power allocation coefficient for each antenna; a modulating unit for modulating data to be transmitted using the modulation system for each antenna stored in the memory when the data to be transmitted is input; and a power adjusting unit for adjusting the power according to the power allocation coefficient for each antenna stored in the memory to transmit the data to be transmitted, modulated at the modulating unit, via a corresponding antenna. A higher performance gain can be provided compared to a conventional open loop V-BLAST system by using a different modulation system and power for each antenna of a transmitter.

Abstract: A hybrid trace back apparatus and a high-speed Viterbi decoding system having the same are disclosed. The hybrid trace back apparatus includes: a register exchanging unit for receiving survivor values of each states from a path metric calculator, and obtaining a block survival value through a register exchange operation as much as a bit length for a block trace back operation; a first storing unit for the register exchange operation; a second storing unit for storing the block survival value obtained through the register exchange operation until the block survival value is written in a block trace back memory; and a block trace back unit for outputting decoded data by performing a block trace back operation while writing a value of the second storing unit.

Abstract: Provided are a flexible bit rate code vector generation method and a wideband vocoder employing the same. This invention implements a flexible bit rate by getting three code vectors which are composed of 24, 16, and 8 pulses, at a time in a search process, through improvement of an algebraic codebook search process in a wideband AMR-WB vocoder. The method includes the steps of: performing a preprocess, wherein the preprocess divides a sub-frame by tracks and decides a pulse position having a maximum value in each track; among a plurality of pulses to be searched, fixing a same number of pulses as the tracks to the position with the maximum value of each track sequentially, and searching optimal positions having a minimum error with a target signal by combining two pulses in two consecutive tracks for the remaining pulses; and creating a code vector with flexible bit rate.

Abstract: Disclosed is an apparatus for performing both FHT (Fast Hadamard Transform) and FFT (Fast Fourier Transform). This apparatus determines the phase coefficients as constantly “1” when performing the FHT, and changes the input order of input data to a reverse order of bits when performing the FFT. In addition, the apparatus, which can process a plurality of input data sets simultaneously, classifies the received signals into multi-path signals and multi-antenna signals, thus processing the multi-path signals separately from the multi-antenna signals, or directly processes multi-antenna signals.

Abstract: A Fast Fourier Transform (FFT) apparatus for selectively performing Fast Hadamard transform (FHT), and a complementary code keying (CCK) modulation/demodulation apparatus using the same. An OFDM module and CCK module are integrated as one module having lower complexity compared to conventional scheme by embodying the CCK modulation using FFT structure in the OFDM module, and embodying the suboptimal and the optimized CCK modulations using FFT structure in OFDM module. CDMA, OFDM, CCK modules may be integrated as single module.

Abstract: A waveform interpolation speech coding apparatus and method for reducing complexity thereof are disclosed. The waveform interpolation speech coding apparatus includes: a waveform interpolation encoding unit for receiving a speech signal, calculating parameters for a waveform interpolation from the received speech signal, and quantizing the calculating parameters; and a realignment parameter calculating unit for restoring a characteristic waveform (CW) using the quantized parameter, calculating a realignment parameter that maximizes a cross-correlation among consecutive CWs for the restored CW.

Abstract: Provided is a receiver of a multi-input multi-output system using multiple antennas, the receiver including: a first multiplying unit for multiplying a vector r received via the antenna by a Hermitian matrix Q; a candidate transmitting vector generating unit for detecting a signal on a lowest modulation order transmitting antenna from the received vector y output from the first multiplying unit, creating as many symbol candidates as the modulation order of the detected signal, and generating a candidate transmitting vector using each symbol candidate; a transmitting vector determining unit for obtaining a distance between each candidate transmitting vector generated by the candidate transmitting vector generating unit and the received vector y to determine a final transmitting vector; and a demodulating unit for demodulating the final transmitting vector determined by the transmitting vector determining unit.

Abstract: Provided is a transmitter for a multi-input multi-output system including: a memory for storing a modulation system and power allocation coefficient for each antenna; a modulating unit for modulating data to be transmitted using the modulation system for each antenna stored in the memory when the data to be transmitted is input; and a power adjusting unit for adjusting the power according to the power allocation coefficient for each antenna stored in the memory to transmit the data to be transmitted, modulated at the modulating unit, via a corresponding antenna. A higher performance gain can be provided compared to a conventional open loop V-BLAST system by using a different modulation system and power for each antenna of a transmitter.

Abstract: A wireless modem is mounted to a terminal for wireless communication, and specifically controls an internal drive clock to reduce power consumption in an active mode. The wireless modem includes: a wireless core module for transmitting and receiving a radio signal; a modulator for converting data to be transmitted into a wireless transmission signal and transmitting the converted signal to the wireless core module; a demodulator for converting the signal received from the wireless core module into reception data; a synchronizer for synchronizing the signal received from the wireless core module; and a clock controller for generating a drive clock of each of the modulator, the demodulator, and the synchronizer. A low power clock controller is divided into six main functional blocks of a synchronizer, an analog controller, a modulator, a channel decoder, a demodulator, and a channel encoder, and has a feature that a clock is input only when a main functional block operates.

Abstract: Provided is a method for channel estimation increasing frequency band efficiency lost by using a pilot, and reducing sensitivity to channel zero, instability, and complexity. The method includes the steps of: (a) generating an i-th symbol block Si including N carriers; (b) performing an inverse fast Fourier transform (IFFT) operation on the i-th symbol block and forming an orthogonal frequency division multiplexing (OFDM) symbol block; (c) attaching a guard interval sample in front of the i-th OFDM symbol block Ui and forming at least one OFDM symbol block Ui,cp; and (d) modeling the formed OFDM symbol block Ui,cp with a channel finite impulse response (FIR) filter h and noise v and estimating channel impulse response using signals yi received through a channel.