RRC signaling is used to configure a user device for N secondary cells SCells on license-exempt channels wi in a frequency hopping channel set W={wi} where i=1, 2, . . . N. Then cross-carrier scheduling is sent on a primary cell PCell to schedule a frequency hopping FH resource block hi on the ith license-exempt channel wi. Based on measurements of at least some of the license-exempt channels wi received from at least the user device, parameters for the frequency hopping are adapted. The FH resource block contains M physical resource blocks, scheduled for the SCell during a FH time interval Tu*L+j by a resource grant sent on a PDCCH of the PCell. In an embodiment the RRC signaling is sent by a micro access node/HeNB on the PCell, the cross carrier scheduling is sent also by the micro access node/HeNB on the PCell, and the PCell lies within an LTE licensed frequency band.