The present disclosure provides a method and a device in a node used for wireless communications: a first receiver, receiving a first signaling group and a second signaling group; and a first transceiver, transmitting a first signal, or, receiving a first signal in a first time-frequency resource pool; herein, the first signaling group and the second signaling group respectively indicate a first index and a second index, the first index being different from the second index; the first signaling group is used to determine the first time-frequency resource pool; the second signaling group is used to determine a second numerical value set; a second numerical value is used to determine a HARQ process number corresponding to the first signal, the second numerical value belonging to the second numerical value set.