Apparatus and method for detecting packet in wireless LAN based on orthogonal frequency division multiplexing

An apparatus for detecting a packet in a Wireless Local Area Network (WLAN) based on Orthogonal Frequency Division Multiplexing (OFDM), the apparatus comprising:

• an autocorrelation average power calculation means for calculating an absolute value of an autocorrelation average power value obtained by delaying a preamble signal of a received signal by half of a preamble length;
• an average power calculation means for calculating an average power value of the received signal;
• a power ratio calculation means for calculating a ratio of the average power value calculated by the average power calculation means to the absolute value of the average power value calculated by the autocorrelation average power calculation means;
• and
• a packet detection means for detecting the packet by using the power ratio calculated by the power ratio calculation means,
• wherein, when a real number part and an imaginary number part of the complex preamble are exchanged in the first half preamble length, the complex preamble signal is a complex preamble signal of the second half of the preamble length.

A method for detecting a packet in a WLAN based on OFDM, the method comprising the steps of:

• (a) when a packet is received from outside, calculating an autocorrelation value by delaying a complex preamble signal of the received packet by half of a preamble length,
• wherein the complex preamble signal is configured to have at least 2 or more samples, and
• wherein the delay of half of the preamble length is configure to be applied immediately after receiving a first sample of the complex preamble signal from the received packet;
• (b) calculating an autocorrelation average power value of the autocorrelation value calculated in the step (a) over the preamble length;
• (c) calculating an absolute value of the autocorrelation average power value calculated in the step (b);
• (d) calculating an average power value of the received packet over the preamble length;
• and
• (e) calculating a power ratio of the average power value to the absolute value of the autocorrelation average power value to detect the packet based on the calculated power ratio.

A method for detecting a packet in a WLAN based on OFDM, the method comprising the steps of:

• (a) when a packet Is received from outside, calculating an autocorrelation value by delaying a complex preamble signal of the received packet by half of a preamble length;
• (b) calculating an autocorrelation average power value of the autocorrelation value calculated in the step (a) over the preamble length:
• (c) calculating an absolute value of the autocorrelation average power value calculated in the step (b);
• (d) calculating an average power value of the received packet over the preamble length;
• and
• (e) calculating a power ratio of the average power value to the absolute value of the autocorrelatlon average power value to detect the packet based on the calculated power ratio,
• wherein, when a real number part and an imaginary number part of the complex preamble are exchanged in the first half preamble length, the complex preamble signal is a complex preamble signal in the second half of the preamble length.