2. A base station, comprising:a generation circuitry
to generate indication information carried by narrowband physical downlink control channel (NPDCCH), which indicates the subcarriers of narrowband physical uplink shared channel (NPUSCH) assigned for UE,
wherein when subcarrier spacing of NPUSCH is 3.75 kHz, the generation circuitry uses the indication information to indicate one subcarrier from possible assigned subcarriers and
when subcarrier spacing of NPUSCH is 15 kHz, the generation circuitry uses the indication information to indicate a set of one or more allocated subcarrier(s) according to a predefined mapping table, wherein the table includes entries for single subcarrier's allocation and entries for multiple subcarriers' allocation,
wherein the number of subcarriers is 1, 3, 6 or 12; and
a transmission circuitry to transmit the indication information carried by NPDCCH.