Abstract: To allocate a number of data elements to a set of carriers, the carriers are divided into N subsets of carriers according to a predetermined carrier criterion whilst the data elements are classified into N groups of data elements according to a predetermined data criterion, N being an integer greater than one. The predetermined data and carrier criterion have a relation on the basis of which the N subsets of carriers are associated one by one to the N groups of data elements. The data elements classified in such a group are then allowed to be modulated only on carriers which form part of the subset associated with this group. In addition, for each subset of carriers and related group of data elements, the distribution is obtained by means of information from subset dependent `required SNR (Signal to Noise Ratio) per data element`-tables and previously carried out SNR measurements for each carrier.