Wireless communications are described for controlling a transmission. A base station may cancel, delay, and/or request a retransmission of a message. The base station may send a control message to control a transmission in a communication network. A wireless device may cancel a transmission (e.g., based on a pre-emption indication), determine a transmission power for a transmission (e.g., based on a power control message), and/or determine a retransmission of a message (e.g., based on a repetition indication).