A radio network controller, RNC, keeps control of how many users to configure on a first transmission time interval, TTI, and how many to configure on a second TTI. For example, a method is performed by the RNC, for configuring at least one radio bearer between a radio base station, RBS, and wireless communication devices. The method comprises sending, from the RNC to the RBS, radio bearer configuration information for controlling a distribution between a first number of wireless communication devices and a second number of wireless communication devices where the first number of wireless communication devices are operating a radio bearer using a first TTI, and the second number of wireless communication devices are operating a radio bearer using a second TTI.