A wireless device may receive measurement report(s) comprising measurement results associated with a second cell. The wireless device may determine, based on initiating a random access process prior to receiving a cell switch MAC CE, a timing advance value associated with the second cell. The wireless device may receive the cell switch MAC CE indicating switching from a first cell to the second cell. The wireless device may perform an uplink transmission on the second cell based on the timing advance value and in response to receiving the cell switch MAC CE.