A method performed by a wireless device for wireless transmission of data to a network node of a wireless communication network. The method comprises receiving, from the network node, at a first time slot, a first scheduling grant instructing the wireless device to transmit first data to the network node at a third time slot, and receiving, from the network node, at a second time slot later than the first time slot but earlier than the third time slot, a second scheduling grant instructing the wireless device to transmit second data to the network node at the third time slot. The method further comprises transmitting, to the network node at the third time slot, the second data, and possibly also the first data, in uplink transmission resources of the third time slot, wherein the transmission is performed in accordance with an instruction.