摘要:
Disclosed are a method for demodulating received signals and an apparatus therefore which can maintain quality of signals and can reduce computational complexity. A demodulation method of a receiving device for receiving a plurality of signals modulated through a M-ary (M is a natural number of 1 or more) modulation method includes: comparing channel frequency response power of a first channel with channel frequency response power of a second channel, selecting M reference signals on the basis of the compared result, selecting corresponding signals paired with respective selected M reference signals, and estimating transmitting signals from the M signal pairs including pairs of the reference signal and the corresponding signal. Accordingly, the computational complexity is reduced from O (M2) to O (M).
摘要:
Disclosed are a method for demodulating received signals and an apparatus therefore which can maintain quality of signals and can reduce computational complexity. A demodulation method of a receiving device for receiving a plurality of signals modulated through a M-ary (M is a natural number of 1 or more) modulation method includes: comparing channel frequency response power of a first channel with channel frequency response power of a second channel, selecting M reference signals on the basis of the compared result, selecting corresponding signals paired with respective selected M reference signals, and estimating transmitting signals from the M signal pairs including pairs of the reference signal and the corresponding signal. Accordingly, the computational complexity is reduced from O (M2) to O (M).
摘要:
Provided are a wireless communication system and a method of performing communication in the same. The wireless communication system includes a terminal configured to classify all subcarriers into a first group and a second group and allocate subcarriers of the first group to first symbols and subcarriers of the second group to the first symbols again to generate and transmit a first transmission signal, a base station configured to allocate the subcarriers of the first group to second symbols and the subcarriers of the second group to third symbols to generate and transmit a second transmission signal, and a relay configured to receive the first and second transmission signals and perform maximum likelihood (ML) determination of frequency domain signals of the first and second transmission signals to estimate the first to third symbols.
摘要:
Provided are a wireless communication system and a method of performing communication in the same. The wireless communication system includes a terminal configured to classify all subcarriers into a first group and a second group and allocate subcarriers of the first group to first symbols and subcarriers of the second group to the first symbols again to generate and transmit a first transmission signal, a base station configured to allocate the subcarriers of the first group to second symbols and the subcarriers of the second group to third symbols to generate and transmit a second transmission signal, and a relay configured to receive the first and second transmission signals and perform maximum likelihood (ML) determination of frequency domain signals of the first and second transmission signals to estimate the first to third symbols.
摘要:
A correlation apparatus and method for frequency synchronization are provided. A frequency synchronization method of a receiver in a broadband wireless access communication system includes acquiring a highest correlation value by conducting a differential correlation of a variable interval between a received signal and a reference signal and performing a frequency synchronization according to the highest correlation value.
摘要:
Disclosed is a radio communication device, and more particularly to a method for estimating a channel and compensating for error occurring in the estimation procedure, for a device for performing a frequency domain signal processing, such as Orthogonal Frequency Division Multiplexing (OFDM) The channel estimation method in a radio communication system includes the steps of: transforming a received OFDM signal into a frequency domain; estimating a channel frequency response (CFR) value from a result value obtained through the transformation by using a pilot signal; transforming the estimated CFR value into a time domain through an extended Inverse Fast Fourier Transform scheme, and detecting a channel impulse response (CIR) value; detecting a delay path position of a channel; modifying a non-ideal autocorrelation function; and compensating the estimated CIR value for error, through use of the detected delay path position and the non-ideal autocorrelation function.
摘要:
A data transmitter and receiver for improving a data rate, and more particularly, to an apparatus and method of transmitting and receiving an orthogonal frequency division multiplexing (OFDM) symbol in which a pilot signal is added to a data signal is provided. The apparatus includes a transmitter including: a pilot adder to add a pilot signal to a data signal; and a guard interval inserting unit to insert a guard interval to the data signal with the added pilot signal, and a receiver including: a guard interval removal unit to remove a guard interval in a received time domain signal; a fast Fourier transform (FFT) unit to transform the time domain signal in which the guard interval is removed to a frequency domain signal; a channel estimator to estimate a channel value from the time domain signal in which the guard interval is removed; an equalizer to equalize the frequency domain signal based on the estimated channel value; and a pilot signal removal unit to remove the pilot signal in the equalized frequency domain signal.
摘要:
A decoding apparatus for decoding input data using a Viterbi algorithm includes a first unit for repetitively performing determination of a survivor path corresponding to each state at each time unit based on the input data and a Trellis diagram, and for generating decision vectors and path number information whenever a branch path is determined. A second unit is provided for storing the decision vectors generated in the first unit and for outputting path information representing each survivor path determined by the stored decision vectors. A third unit stores the path number information output from the first unit and the path information output from the second unit, and deletes the branch path information corresponding to the path number information of the first unit from the stored path information, while retracing the previous states during the time when the branch path to be deleted does not overlap the other survivor path having a branch path connected to the next state. The third unit generates decoded data corresponding to input data based on the finally remaining survivor path.
摘要:
In a method of estimating a signal-to-interference ratio (SIR), a first average channel power per slot of a first channel that is under a fading environment is estimated. A second average channel power per slot of a second channel that is under a fading environment substantially the same as the first channel is estimated, wherein the first and second channels are multiplexed. A second signal power attenuation ratio of the second channel is calculated using the second average power per slot of the second channel. A third average power per slot of the first channel is calculated using the first average power per slot of the first channel and a reciprocal of the second signal power attenuation ratio of the second channel.
摘要:
An asymmetric error correction apparatus and method, and clock recovering apparatus and data recovering apparatus for a system for reading data from an optical recording medium such as a CD or DVD that has a multi-level input signal and irregular characteristic of zero-crossing transition. The signal inputted from the optical recording medium is digitized, and a zero-crossing detector extracts four sequential samples and detects a zero-crossing point from the two intermediate samples. An asymmetric error detector judges an asymmetric state and asymmetric polarity of the digital signal from a sum of the two side samples among the four samples if the zero-crossing point is detected. A correction section accumulates the judged asymmetric polarities, judges an asymmetric error of the digital signal if the accumulated value exceeds a predetermined threshold, and corrects the asymmetric error of the read signal caused by an inaccurate pit length.