Embodiments herein relate to a method in a radio base station for transmitting information of an allocation of a radio resource allocated to a second user equipment. The radio base station is arranged to serve a first user equipment and the second user equipment in a cell of a radio communications network. The radio resource in the cell comprises Physical Resource Blocks that are organized in radio frames comprising subframes. The radio base station allocates a radio resource to the second user equipment in a subframe of the cell based on a frequency hopping scheme of the first user equipment. Also, the radio base station transmits a message to the second user equipment, which message indicates the allocated radio resource.