Abstract: In a method for estimating a signal-to-noise ratio (SNR) of an orthogonal frequency division multiplexing (OFDM) wireless mobile communication system, noise is estimated from adjacent received signals of at least two adjacent subcarriers and received signals of subcarriers, noise power is calculated by calculating a mean square value of the estimated noise by summing squares of the estimated noise, a mean square value of the received signals is calculated by summing squares of the received signals, signal power is calculated by subtracting the noise power from the mean square value of the received signals, and the SNR is calculated using the signal power and the noise power. Thus, the method of the present invention having low complexity can estimate an SNR efficiently regardless of channel changes on a frequency axis when one OFDM symbol includes preamble data.

Abstract: A method of determining a variable quantization step size is disclosed. In the method of determining a variable quantization step size, a channel characteristic parameter is obtained in order to calculate a quantization step size (?) used in channel decoding. The quantization step size (?) is variably determined based on the channel characteristic parameter. Therefore, the method of determining a variable quantization step size may improve channel decoding.

Abstract: An orthogonal frequency division multiplexing (OFDM) system and a method of controlling preamble power of the OFDM system are provided. The method includes detecting a present preamble power of a certain base station among a plurality of base stations and a preamble influence factor of the certain base station; detecting a preamble influence factor of at least one neighboring base station of the certain base station; and determining a new preamble power of the certain base station based on at least one among the present preamble power, the preamble influence factor of the certain base station, and the preamble influence factor of the at least one neighboring base station.

Abstract: In a method for estimating a signal-to-noise ratio (SNR) of an orthogonal frequency division multiplexing (OFDM) wireless mobile communication system, noise is estimated from adjacent received signals of at least two adjacent subcarriers and received signals of subcarriers, noise power is calculated by calculating a mean square value of the estimated noise by summing squares of the estimated noise, a mean square value of the received signals is calculated by summing squares of the received signals, signal power is calculated by subtracting the noise power from the mean square value of the received signals, and the SNR is calculated using the signal power and the noise power. Thus, the method of the present invention having low complexity can estimate an SNR efficiently regardless of channel changes on a frequency axis when one OFDM symbol includes preamble data.

Abstract: A method of determining a variable quantization step size is disclosed. In the method of determining a variable quantization step size, a channel characteristic parameter is obtained in order to calculate a quantization step size (?) used in channel decoding. The quantization step size (?) is variably determined based on the channel characteristic parameter. Therefore, the method of determining a variable quantization step size may improve channel decoding.

Abstract: A convolution code generator according to the present invention simultaneously generates convolution codes with respect to input data word by word when a digital signal processor in which the convolution code generator can be installed has a bus configuration of a broad data width.