The present disclosure discloses a method for selecting consecutive resource blocks (RBs) on an available frequency band and an associated base station (BS). The method comprises the step of determining a minimum possible window size and a maximum possible window size for each of selected fragments of the frequency band (S210), wherein all RBs on a selected fragment together are sufficient to empty a transmission buffer. The method further comprises the step of determining candidate fragments to be searched through (S220), by defining a reference window size range by a minimum value of minimum possible window sizes of the selected fragments and a minimum value of maximum possible window sizes of the selected fragments and determining a selected fragment, whose window size range defined by its minimum possible window size and maximum possible window size intersects with the reference window size range, as one of the candidate fragments. The method also comprises the step of searching through the candidate fragments using window sizes which fall within the reference window size range to select a minimum number of consecutive RBs sufficient to empty data stored in the transmission buffer (S240).