A wireless communication system, in which a redundancy bit is transmitted from a first communication device to a second communication device when the second communication device fails to decode the encoded bits, includes a processor. The processor selects communication patterns that respectively satisfy a requested quality, calculates, for each of the selected communication patterns, a transmission data length that indicates a length of the redundancy bit, calculates, for each of the selected communication patterns, a transmission latency between the first communication device and the second communication device based on the calculated transmission data length, and generates a retransmission parameter corresponding to a communication pattern with lowest transmission latency among the selected communication patterns. The first communication device transmits the redundancy bit according to the retransmission parameter, and the second communication device decodes the encoded bits by using the redundancy bit according to the retransmission parameter.