Apparatus for transmitting data in a frame with subframes of a wireless communication system, each subframe being either an uplink subframe accommodating uplink signal, a downlink subframe accommodating downlink signal or a special subframe including a downlink signal portion as well as an uplink signal portion, the apparatus comprising: a receiver for receiving a control signal including a special subframe configuration specifying the length of the uplink and/or downlink portion of the special subframe; a mapper for mapping user data and/or control data including feedback information in a transmission time interval, TTI, onto one subframe, wherein the length of a second TTI for mapping onto the uplink portion of a special subframe is shorter than a first TTI for mapping onto an uplink subframe; and a transmitter for transmitting the mapped user data and/or control data including feedback information, characterized in that the special subframe configuration takes a value out of a value set in which: a first value indicates length of the uplink portion of the special subframe which is not sufficient to accommodate the user data and/or control data including feedback information in the second TTI, and a second value indicates length sufficient to accommodate the user data and/or control data including feedback information in the second TTI but not in the first TTI; and the mapper is configured to: - map onto the uplink portion physical layer signals including sounding reference signals if the special subframe configuration takes the first value; and - map onto the uplink portion control data including positive or negative acknowledgements for downlink data and/or channel state information if the special subframe configuration takes the second value; or - map onto the uplink portion user data if the special subframe configuration takes the second value. a receiver for receiving a control signal including a special subframe configuration specifying the length of the uplink and/or downlink portion of the special subframe; a mapper for mapping user data and/or control data including feedback information in a transmission time interval, TTI, onto one subframe, wherein the length of a second TTI for mapping onto the uplink portion of a special subframe is shorter than a first TTI for mapping onto an uplink subframe; and a transmitter for transmitting the mapped user data and/or control data including feedback information, characterized in that the special subframe configuration takes a value out of a value set in which: a first value indicates length of the uplink portion of the special subframe which is not sufficient to accommodate the user data and/or control data including feedback information in the second TTI, and a second value indicates length sufficient to accommodate the user data and/or control data including feedback information in the second TTI but not in the first TTI; and the mapper is configured to: - map onto the uplink portion physical layer signals including sounding reference signals if the special subframe configuration takes the first value; and - map onto the uplink portion control data including positive or negative acknowledgements for downlink data and/or channel state information if the special subframe configuration takes the second value; or - map onto the uplink portion user data if the special subframe configuration takes the second value. a first value indicates length of the uplink portion of the special subframe which is not sufficient to accommodate the user data and/or control data including feedback information in the second TTI, and a second value indicates length sufficient to accommodate the user data and/or control data including feedback information in the second TTI but not in the first TTI; and the mapper is configured to: - map onto the uplink portion physical layer signals including sounding reference signals if the special subframe configuration takes the first value; and - map onto the uplink portion control data including positive or negative acknowledgements for downlink data and/or channel state information if the special subframe configuration takes the second value; or - map onto the uplink portion user data if the special subframe configuration takes the second value. - map onto the uplink portion physical layer signals including sounding reference signals if the special subframe configuration takes the first value; and - map onto the uplink portion control data including positive or negative acknowledgements for downlink data and/or channel state information if the special subframe configuration takes the second value; or - map onto the uplink portion user data if the special subframe configuration takes the second value.