The present disclosure provides a method of determining a DTX cause at an access node, comprising: transmitting, to a User Equipment (UE), an Uplink (UL) grant and a Downlink (DL) assignment in a same DL subframe; detecting whether Discontinuous Transmission (DTX) of at least one of UL data to be transmitted in response to the UL grant received by the UE and Hybrid Automatic Repeat Request (HARQ) Acknowledgement (ACK)/Negative Acknowledgement (NACK) to be transmitted in response to DL data related to the DL assignment received by the UE occurs; and determining a cause of the DTX based on a result of the DTX detection. The present disclosure further provides an access node using the method and a computer program product.