Before the terminal performs grant free transmission, the base station usually needs to specify available uplink transmission resources for the terminal in advance, such as an uplink pilot resource, a time domain resource, and a frequency domain resource. There are a plurality of types of time-frequency resources, as shown in FIG. 2, the time-frequency resources include downlink-only time-frequency resources, uplink-only time-frequency resources, time-frequency resources including downlink time-frequency resources in the majority, and time-frequency resources including uplink time-frequency resources in the majority. Usually, the time-frequency resources may be distinguished based on a quantity NsymbUL of orthogonal frequency division multiplexing (Orthogonal Frequency Division Multiplexing, OFDM) symbols used for uplink transmission. It is assumed that one subframe includes 14 OFDM symbols, for a downlink-only subframe, NsymbUL=0, and for an uplink-only subframe, NsymbUL=14. When there are a relatively small quantity of symbols in a subframe that are used for uplink transmission, there are a relatively small quantity of corresponding time-frequency resources that can be used for grant free transmission; on the contrary, when there are a relatively large quantity of symbols in a subframe that are used for uplink transmission, there are a relatively large quantity of corresponding time-frequency resources that can be used for grant free transmission.
