A method and network node of a radio network, for enabling a User Equipment (UE) to save power in radio communication with the network node. The network node sets a waiting threshold for the UE and communicates data with the UE over a radio link. The network node also obtains traffic characteristics pertaining to the radio communication, and predicts a waiting time until next data is to be communicated with the UE based on the traffic characteristics. The network node further triggers the UE to enter a Discontinuous Reception (DRX) sleep when the predicted waiting time is longer than the waiting threshold. Thereby, power can be saved in the UE by immediately going to sleep after the last data.