Data Transmission Method and Apparatus

An apparatus comprising:

• a processor;
• and
• a non-transitory computer readable medium storing a program to be executed by the processor, the program including instructions for:
• when a first device transmits at least one transport block (TB) for the first time, sending, by the first device, first control information to a second device, wherein the first control information comprises a modulation and coding scheme (MCS) field, and the MCS field comprises at least one of information about a modulation scheme used when the TB is sent and or information about a transport block size (TBS);
• and
• when the first device retransmits the TB, sending, by the first device, second control information to the second device, wherein the second control information comprises a first field but does not comprise the MCS field, and the first field comprises information about a relationship between retransmitted data and the TB.