Method performed by a first network node (111) for handling scheduling of wireless devices. The first network node (111) obtains information about a first type of time resource used by HD-FDD wireless devices (151). The first network node (111) also obtains information about a second type of time resource not used by the HD-FDD wireless devices (151) due to a transition at the HD-FDD wireless devices (151) between UL and DL. The first network node (111) schedules a first wireless device out of FD-FDD wireless devices (152) during the second type of time resource, based on the obtained information about the second type. The first network node (111) decides whether or not to schedule a second wireless device out of the FD-FDD wireless devices (152) during the first type of time resource, based on the obtained information about the first type, and further based on whether first conditions are met.