Abstract: A method for expansion of communication capacity in a radio communication system (1) including a multi-beam antenna system (3) is described. The antenna beams (5) are divided into groups, where the geographical coverage of each group defines a respective sub-sector (7.1,7.2). The sub-sectors in conjunction provide coverage in a radio sector serviced by the communications system (1). A number of carriers are connected to the multi-beam antenna system (3) via a switch (11) and a combiner network (9). The switch (11) allows each carrier to be selectively switched to the sub-sectors via the combiner network (9). In order to expand communication capacity, at least one new carrier is provided. The antenna beam groups and the respective sub-sectors are re-defined such that the number of sub-sectors 15 (8.1-8.4) is increased. In response to the re-definition of the antenna beam groups and sub-sectors (8.1-8.4), carrier to beam connections are re-configured.