Transmission apparatus, reception apparatus, communication system, communication method, and data processing method

A communication method executed by a User Equipment (UE), the method comprising:

• generating a Packet Data Convergence Protocol (PDCP) data comprising a header, user plane data, and a Message Authentication Code for Integrity (MAC-I), wherein the header includes a first field indicating whether or not the data needs integrity protection and a second field indicating whether the PDCP data is first data including the MAC-I or second data not including the MAC-I;
• and
• transmitting, to an apparatus, an integrity protected PDCP data.

A communication method executed by an apparatus, the method comprising:

• generating a Packet Data Convergence Protocol (PDCP) data comprising a header, user plane data, and a Message Authentication Code for Integrity (MAC-I), wherein the header includes a first field indicating whether or not the data needs integrity protection and a second field indicating whether the PDCP data is first data including the MAC-I or second data not including the MAC-I;
• and
• transmitting, to a User Equipment (UE), an integrity protected PDCP data.