Patent ID: 6990627

Claim:
A digital radio communication system comprising: a transmitting-side apparatus that includes: an error detection coding section that sets a plurality of error detection units for each of a plurality of transmission units and performs error detection coding of data for each error detection unit; an M-ary modulation section that, for each transmission unit, arranges the error detection coded data of the error detection units into the corresponding transmission unit and modulates the transmission unit; and a transmitting section that radio transmits the modulated transmission units in a signal; and a receiving-side apparatus that includes: a receiving section that receives the signal transmitted from said transmitting-side apparatus; a first decoding section that decodes the received signal; an error detecting section that detects, for each error detection unit in the received signal, the occurrence of a decoding error in said first decoding section; a replica generating section that generates a replica of a part of the received signal using a bit, belonging to an error detection unit, for which an error was not detected; an interference canceling section that subtracts the replica from the received signal to produce an interference cancelled signal; a likelihood generating section that demodulates the interference cancelled signal to generate a candidate likelihood value of a bit corresponding to an error detection unit having a detected error; a likelihood modifying section that modifies said candidate likelihood value in accordance with a result of error detection in said error detecting section; and a second decoding section that performs error correction decoding of the interference cancelled signal using the modified candidate likelihood value.