The invention relates to a universal mapping of resource elements (REs) to enhanced resource element groups (eREG) that applies to both the PDCCH and PDSCH regions; the mapping is universal since it is not user or cell-specific but applies to the resource block pairs irrespective of the actual reference signals used. The mapping is such that all REs of the resource block pair are assigned to one out of a plurality of eREGs. According to the mapping, the REs are sequentially assigned to the eREGs, in predetermined orders. Within an OFDM symbol a pair of REs is assigned to the same eREG, wherein the two REs are spaced apart from each other by 3 or 6 subcarriers.