1. A method, performed by a wireless communication system, for managing operation of multiple Radio Access Technologies, RATs, a first type of wireless devices being enabled to communicate wirelessly in the wireless communication system according to a first RAT, via one or more base stations, wherein, in the first RAT, resource blocks for uplink and/or downlink communication are allocated according to a predetermined multiple access structure based on frequency division and/or time division, wherein the method comprises:excluding for allocation to the first type of wireless devices one or more of said resource blocks of the first RAT; and
allocating said excluded one or more resource blocks of the first RAT for use by a second type of wireless devices and for wireless communication according to a second RAT, via said one or more base stations, wherein the one or more resource blocks of the first RAT are multiple resource blocks that are continuous in at least one of frequency or time, thereby forming a continuous block, wherein the second RAT uses subblocks of the continuous block as resource blocks of the second RAT and uses at least one of a frequency division factor or a time division factor that is different than that used by the first RAT, thereby enabling the second RAT to define a resource block of the second RAT in relation to dimensions of a resource block of the first RAT;
wherein the first RAT is GSM,
wherein said second RAT is a RAT having more carriers, but of more narrow bandwidth, than in GSM.