A wireless communication system includes: a multiple number of mobile station apparatuses that transmit code bits obtained by applying error-correction coding to information bits; a relay station apparatus that receives code bits from the multiple mobile station apparatuses, applies network coding on the code bits and transmits the network-code bits; and a base station apparatus that receives and decodes the code bits and the network-code bits, wherein the base station apparatus, when decoding the received code bits, performs iteration decoding by regarding the received code bits as a serially concatenated code of network coding and error correction coding. Accordingly, decoding is performed by regarding the network code and the error correction code as a serial concatenated code, it is possible to obtain diversity with a simple configuration.