It is presented a method performed by a network node of a wireless communication network for scheduling a wireless device in uplink. An uplink signal structure is configured to be used by the wireless device and the network node, wherein the uplink signal structure defines transmission subframes divided into symbol periods. The network node applies a short Transmission Time Interval, sTTI, scheduling interval, wherein each sTTI is shorter in time than a subframe and each sTTI comprises at least one symbol period. The method comprises: transmitting a control information message to the wireless device for an sTTI scheduling interval, the control information message comprising uplink scheduling information assigned to the wireless device, the uplink scheduling information indicating a position and a length for at least one of a reference signal and data in the uplink sTTI.