Apparatus and method for transmitting and receiving signal based on QAM constellation

A receiving apparatus for receiving signal in a wireless communication system, the apparatus comprising:

• a processor, a memory, and a radio frequency unit,
• wherein the processor executes a program stored in the memory to perform:
• receiving a signal from a transmitting apparatus;
• and
• demodulating the signal into a symbol based on a predetermined 2q-quadrature amplitude modulation (QAM) constellation including 2q symbol decision regions corresponding to a q-bit symbol, respectively,
• wherein when the processor performs the demodulating the signal into a symbol based on a predetermined 2q-QAM constellation, the processor performs:
• determining a first combined decision region including a symbol decision region in which the signal is located among four first combined decision regions to determine a first two bits of the symbol;
• determining a nth combined decision region including a symbol decision region in which the signal is located among four nth combined decision regions to determine a nth two bits of the symbol;
• and
• determining a final symbol decision region which is commonly included in the determined first combined decision region and the determined nth combined decision region, and
• wherein q is a multiple of 2 greater than 2, and n is an integer.

A method for receiving signal in a wireless communication system, the method comprising:

• receiving a signal from a transmitting apparatus;
• and
• demodulating the signal into a symbol based on a predetermined 2q-quadrature amplitude modulation (QAM) constellation including 2q symbol decision regions corresponding to a q-bit symbol, respectively,
• wherein the demodulating the signal into a symbol based on a predetermined 2q-QAM constellation comprises:
• determining a first combined decision region including a symbol decision region in which the signal is located among four first combined decision regions to determine a first two bits of the symbol;
• determining a nth combined decision region including a symbol decision region in which the signal is located among four nth combined decision regions to determine a nth two bits of the symbol;
• and
• determining a final symbol decision region which is commonly included in the determined first combined decision region and the determined nth combined decision region, and
• wherein q is a multiple of 2 greater than 2, and n is an integer.