Automatic gain control device and method in orthogonal frequency division multiplexing system with DC offset compensation function, and recording medium storing program containing the method

An AGC (automatic gain control) method in an OFDM (orthogonal frequency division multiplexing) system, comprising:

• (a) performing coarse AGC through a DC offset cancellation in a short training sequence interval when an input signal is detected, the AGC being performed by subtracting an energy of the DC offset from an energy of the input signal and using an energy of the DC offset cancelled ideal signal;
• (b) performing a coarse frequency offset search and cancellation in the short training sequence interval;
• (c) performing fine AGC through a DC offset cancellation in a long training sequence interval, the AGC being performed by subtracting the energy of the DC offset from the energy of the input signal and using the energy of the DC offset cancelled ideal signal;
• and
• (d) performing a fine frequency offset search and cancellation in the long training sequence interval.

In an AGC (automatic gain control) method in an OFDM (orthogonal frequency division multiplexing) system, a recording medium including a program comprising:

• (a) performing coarse AGC through a DC offset cancellation in a short training sequence interval when an input signal is detected, the AGC being performed by subtracting an energy of the DC offset from an energy of the input signal and using an energy of the DC offset cancelled ideal signal;
• (b) performing a coarse frequency offset search and cancellation in the short training sequence interval;
• (c) performing fine AGC through a DC offset cancellation in a long training sequence interval, the AGC being performed by subtracting the energy of the DC offset from the energy of the input signal and using the energy of the DC offset cancelled ideal signal;
• and
• (d) performing a fine frequency offset search and cancellation in the long training sequence interval.