Aspects and embodiments provide a method of allocating frame resource elements in a wireless communication network for the purpose of channel estimation, and a base station and computer program product operable to perform that method. One aspect provides a method of allocating resource elements in a wireless communication network. The method comprises: determining a channel estimate associated with each user equipment to be scheduled in a given frame; assessing whether a validity time associated with each channel estimation value, e.g. CSI, associated to each user equipment is still valid or should be considered as expired; and allocating the frame resource elements to either channel estimation, when the current channel estimation is not anymore valid, or else to data transmission, when it is still valid. The validity time comprises a number of frames and is selected according to an associated mobility of the user equipment, wherein for semi-static UEs the current channel estimation is considered to be valid for a longer time. Aspects and embodiments provide a method for an adaptive and user-centric frame design in massive MIMO that takes into account mobility of UEs and thus may mitigate waste of resource associated with use for unnecessary channel estimation purposes.