A node receives a first information block comprising configuration information of a target sub-band and a first signaling determining a target time-frequency resource set; and transmits a target signal with a target Tx power; the target Tx power is equal to a smaller value between a first Tx power and a target power upper limit, and the target time-frequency resource set determines a first parameter value which the first Tx power is linear with; a power class of the node determines a second parameter value, the second parameter value determining a value range of the target power upper limit; a relation between the target time-frequency resource set and the target sub-band or the configuration information is used to determine at least one of the value range of the target power upper limit or the first Tx power. Link performance is ensured.