During an RRC Connection setup or resume procedure, a user equipment may explicitly identify itself to the network using Msg3. Rather than using the spare bit or including additional bits in Msg3, one or more values of the LCID field of the MAC sub-header of the MAC PDU may be used to identify a reduced capability user equipment. The one or more LCID field values that can identify a reduced capability user equipment may also be configured to identify a common control channel service data unit size. A plurality of LCID field values may be defined to identify varies types of RedCap UEs.