Apparatus for transmitting and receiving signal

An operation method of an apparatus for transmitting and receiving signal, the operation method comprising:

• receiving a reception signal through a channel and demodulating the reception signal into a reception symbol and a channel estimation value corresponding to the reception signal;
• detecting a modulation type of the reception signal;
• calculating a first status data based on a first value obtained by zero-forcing the reception symbol and a second value obtained by squaring the channel estimation value;
• calculating a second status data based on the second value;
• estimating bit information with respect to the reception symbol based on the modulation type, the first status data, and the second status data;
• and
• performing decryption on the bit information,
• wherein the estimating of the bit information comprises:
• determining a log likelihood ratio (LLR) signal, which comprises a plurality of first bits representing a real part and a plurality of second bits representing an imaginary part, by using a piecewise linear function representing the reception symbol as a plurality of linear functions by dividing the reception symbol into a plurality of sections and approximating each of the plurality of sections by a linear function.

An apparatus for transmitting and receiving signal, the apparatus comprising:

• a transceiver configured to receive a reception signal through a channel and demodulate the reception signal into a reception symbol and a channel estimation value corresponding to the reception signal;
• a status data calculator configured to detect a modulation type of the signal, calculate a first status data based on a first value obtained by zero-forcing the reception symbol and a second value obtained by squaring the channel estimation value, and calculate a second status data based on the second value;
• an LLR calculator configured to estimate a log likelihood ratio (LLR) signal of n bits comprising a plurality of first bits representing a real part and a plurality of second bits representing an imaginary part with respect to the reception symbol based on the modulation type, the first status data, and the second status data;
• and
• a lookup table storing a mapping relationship between the reception symbol and the plurality of first bits or the plurality of second bits depending on the modulation type,
• wherein the LLR calculator is further configured to determine the LLR signal by using a piecewise linear function representing the reception symbol as a plurality of linear functions by dividing the reception symbol into a plurality of sections and approximating each of the plurality of sections by a linear function.