A base station transmits a message to wireless devices in connected mode. The message comprises an initial subframe allocation bitmap indicating an initial plurality of subframes including an initial plurality of special subframes. After an increase in the number of wireless devices or traffic load by an amount greater than a load value, the base station transmits a second message. The second message comprises an updated subframe allocation bitmap indicating a second plurality of subframes including an updated plurality of special subframes. The updated plurality of special subframes includes a smaller number of special subframes than the initial plurality of special subframes.