A method in a radio access node for communicating with a radio terminal in a network system, comprising the following steps: transmitting (S120) to the radio terminal a mapping between a first set of identifiers and a second set of identifiers, wherein each identifier in the first set of identifiers is represented using fewer bits than corresponding identifiers in the second set of identifiers, and communicating (S130) with the radio terminal using at least one identifier in the first set of identifiers, the method being characterized in that : - each identifier identifies a reference signal in the network system, - at least one of the identifiers in the first and/or second set of identifiers identifies a reference signal of one of a beam (120-1, 120-2, 120-3, 130-1, 130-2, 130-3, 130-4), and a beam (120-1, 120-2, 120-3, 130-1, 130-2, 130-3, 130-4) within a cell , and - communicating (S130) with the radio terminal comprises transmitting (S270) a command to the radio terminal , the command including one of the identifiers in the first set of identifiers and instructing the radio terminal to switch from a beam (120-1, 120-2, 120-3, 130-1, 130-2, 130-3, 130-4) serving the radio terminal to a different beam (120-1, 120-2, 120-3, 130-1, 130-2, 130-3, 130-4) identified by one of the identifiers in the second set of identifiers. transmitting (S120) to the radio terminal a mapping between a first set of identifiers and a second set of identifiers, wherein each identifier in the first set of identifiers is represented using fewer bits than corresponding identifiers in the second set of identifiers, and communicating (S130) with the radio terminal using at least one identifier in the first set of identifiers, the method being characterized in that : - each identifier identifies a reference signal in the network system, - at least one of the identifiers in the first and/or second set of identifiers identifies a reference signal of one of a beam (120-1, 120-2, 120-3, 130-1, 130-2, 130-3, 130-4), and a beam (120-1, 120-2, 120-3, 130-1, 130-2, 130-3, 130-4) within a cell , and - communicating (S130) with the radio terminal comprises transmitting (S270) a command to the radio terminal , the command including one of the identifiers in the first set of identifiers and instructing the radio terminal to switch from a beam (120-1, 120-2, 120-3, 130-1, 130-2, 130-3, 130-4) serving the radio terminal to a different beam (120-1, 120-2, 120-3, 130-1, 130-2, 130-3, 130-4) identified by one of the identifiers in the second set of identifiers. - each identifier identifies a reference signal in the network system, - at least one of the identifiers in the first and/or second set of identifiers identifies a reference signal of one of a beam (120-1, 120-2, 120-3, 130-1, 130-2, 130-3, 130-4), and a beam (120-1, 120-2, 120-3, 130-1, 130-2, 130-3, 130-4) within a cell , and - communicating (S130) with the radio terminal comprises transmitting (S270) a command to the radio terminal , the command including one of the identifiers in the first set of identifiers and instructing the radio terminal to switch from a beam (120-1, 120-2, 120-3, 130-1, 130-2, 130-3, 130-4) serving the radio terminal to a different beam (120-1, 120-2, 120-3, 130-1, 130-2, 130-3, 130-4) identified by one of the identifiers in the second set of identifiers. <EOS>