In a heterogeneous wireless network that includes a macro base station and one or more micro base stations, a wireless device to wirelessly transmit, in a first time slot at a first position in a first transmission subframe, data over a first physical communication channel. An ACK/NACK control message is received over a backhaul network connection a first time period after the first time slot. A response message is transmitted to the wireless device such that when the control message is received prior to the second time slot, then the response message uses data reception information from the control message and when the control message is not received prior to the second time slot, then the response message indicates that the data was successfully received.