Source nodes in an International Mobile Telecommunications (IMT)-advanced 4G network transmit data on uplink channels to a relay node and a BS using a channel code. The relay node decodes independently the data received from each source node, and applies network coding to data correctly decoded, and transmits the encoded data to the BS. The BS decodes the encoded data transmitted by the sources nodes and the relay nodes cooperatively via a turbo decoding process. The data from each source node are decoded by soft-input soft-output single user decoders and are decoded, together with the data from the relay node, by a soft-input soft-output multi-user decoder.