Apparatus and method for detecting packet of zero-padded OFDM signal

A packet detecting method, comprising:

• calculating a cross-correlation value of a reception signal received from the outside, and delaying the calculated cross-correlation value by a predetermined sample time;
• calculating a power value of the reception signal;
• and
• determining if a packet exists in the reception signal by comparing the delayed cross-correlation value with the calculated power value, and detecting the corresponding packet,
• wherein the reception signal includes a zero-padded symbol;
• the zero-padded symbol includes time-domain preamble samples and zero-padded suffix samples;
• the cross-correlation calculator delays the reception signal by a zero-padded sample time;
• the cross-correlation calculator delays the reception signal by a time-domain preamble samples time;
• the cross-correlation calculator delays the reception signal by a zero-padded suffix samples time;
• and
• the power calculator accumulates the power value during an interval defined below the zero-padded sample time.

A packet detecting apparatus, comprising:

• a cross-correlation calculator for calculating a cross-correlation value of a reception signal received from the outside and delaying the calculated cross-correlation value by a predetermined sample time;
• a power calculator for calculating a power value of the reception signal;
• and
• a packet detector for determining if a packet exists in the reception signal by comparing the delayed cross-correlation value with the calculated power value, and detecting the corresponding packet
• wherein the packet detector determines if the packet exists in the reception signal in each packet searching interval, and determines that the packet exists in the reception signal when the delayed cross-correlation value is greater than a predetermined power value and greater than a first false alarm threshold value in each packet searching interval.