The present disclosure provides a method used in user equipment, comprising: receiving an indication for enabling a sub-physical resource block enhancement mode from a base station through a media access control (MAC) random access response (RAR) or radio resource control signaling, wherein one or more bits in the MAC RAR indicate that the sub-physical resource block enhancement mode is to be applied to transmission of a random access message 3 “Msg3” and subsequent PUSCHs; enabling the sub-physical resource block enhancement mode in response to the indication, and receiving downlink control information (DCI) from the base station, the DCI comprising a subcarrier indication field indicating the number of subcarriers used for a physical uplink shared channel (PUSCH) and locations of the subcarriers; and transmitting the PUSCH according to the subcarrier indication field.