Information processing method and system, sending device and receiving device

The invention discloses an information processing method and system, a sending device and a receiving device. The information processing method comprises the following steps of mapping the inputted first bit information by adopting a second mapping rule to obtain the second bit information; determining the third bit information according to the first bit information or the second bit information,and performing forward error correction coding on the third bit information; mapping the third bit information subjected to forward error correction coding by adopting a first mapping rule to obtain symbol information, and sending the symbol information, wherein the first mapping rule is Gray mapping, the second mapping rule is the mapping from the fourth bit information corresponding to the sameconstellation point to the fifth bit information, the fourth bit information is the bit information corresponding to the constellation point under the first mapping rule, and the fifth bit informationis the bit information cor