Data transmission method, terminal device, and network side device

A terminal device, comprising:

• memory comprising instructions, and at least one receiver, and at least one transmitter and at least one processor in communication the memory:
• the processor configured to encode a first identifier by using a first code word which is selected from at least one code word;
• the transmitter, configured to send the encoded first identifier to a network side device;
• the receiver, configured to receive a second identifier sent by the network side device;
• and
• the processor is further configured to decode the second identifier by using the first code word, wherein
• the processor is further configured to:
• when the decoded second identifier is the same as the first identifier, encode subsequent data by using the first code word;
• and
• the transmitter is further configured to send the encoded subsequent data to the network side device.