Apparatus and method for channel quality estimation and link adaptation in orthogonal frequency division multiplexing (OFDM) wireless communication system

An apparatus for channel quality estimation and link adaptation, comprising:

• an analog-to-digital converter for converting an externally received signal to a digital signal;
• a guard time remover for removing a guard time from the converted digital signal;
• a fast Fourier transform (FFT) unit for converting the signal removed of the guard time to a signal in a frequency domain;
• a channel quality estimator for measuring a quality status of a physical layer of a channel in consideration of a signal-to-noise ratio and a delay spread, using the converted digital signal and the signal in the frequency domain, the physical layer to provide the calculated signal-to-noise ratio and a normalized accumulated power estimate to a media access control layer;
• and
• a link adaptor for determining parameters including transmit power, data modulation mode, and data rate using the measured quality status of the channel and a protocol for acknowledging a normal data transmission at a data transmitter and a data receiver, and performing a link adaptation.

A recording medium with a built-in program, said recording medium including a method for channel quality estimation and link adaptation, the program comprising:

• estimating a channel gain and a noise power, and measuring a signal-to-noise ratio in consideration of the estimated channel gain and the estimated noise power;
• calculating a correlation value between an externally received preamble signal and a known preamble signal, and estimating a delay spread;
• calculating a maximum of the correlation value and determining a normalized accumulated power estimate using the calculated maximum;
• measuring a quality status of a channel in consideration of the measured signal-to-noise ratio and the estimated delay spread;
• and
• determining parameters including transmit power, data modulation mode, and data rate using the measured quality status of the channel and a protocol for acknowledging a normal data transmission at a data transmitter and a data receiver, and performing a link adaptation.