Patent ID: 7761777

Claim:
A soft decision demapping method suitable for higher-order modulation for an iterative decoder in a 2 N phase modulation system, N being a positive integer, said method being performed by an error correction apparatus and comprising the steps of: defining, by a mean for defining of the error correction apparatus, distance values Pi between a received signal r and coordinates Si of constellation dots; obtaining, by a mean for obtaining of the error correction apparatus, a difference between a maximum value of distance values Pi when a first bit or Most Significant Bit (MSB) is 0 and a maximum value of distance values Pi when the first bit is 1, during a soft decision of the first bit of N-bit received signal symbol; acquiring, by a mean for acquiring of the error correction apparatus, a difference between a maximum value of distance values Pi when a second bit is 0 and a maximum value of distance values Pi when the second bit is 1, during a soft decision of the second bit of the N-bit received signal symbol; and deriving, by a mean for deriving of the error correction apparatus, a difference between a maximum value of distance values Pi when an Nth bit is 0 and a maximum value of distance values Pi when the Nth bit is 1, during a soft decision of the Nth bit of the N-bit received signal symbol.