Support of mobility for a communication device (120) being served in a serving beam (115a) transmitted by a first network node (110) comprised in a wireless communication network (100). The first network node (110) and the communication device (120) obtains (301a, 302; 701, 901) a first information set comprising predetermined identifiers identifying reference signals, respectively. The first network node (110) maintains (310; 904) a third information set that associates one or more candidate beams (115b, 116a-c), other than the serving beam (115a), with one or more predetermined identifiers of the first information set, which one or more predetermined identifiers identify reference signals that are being transmitted in said one or more candidate beams (115, 116a-c).