Method and apparatus for bit to simbol mapping in wireless communication system

A base station determines one or more first bits to be mapped on at least one quadrature amplitude modulation (QAM) symbols and one or more second bits to be mapped on one or more frequency shift keying (FSK) symbols among bits included in an encoded input bit stream in a wireless communications system. One or more QAM symbols are mapped since gray coding is performed on at least one first bit. At least one second bit is mapped on at least one FSK symbol based on a hamming distance between the second bits.