5.5 Interactions between RRC and lower layers in the C plane

25.3013GPPRadio interface protocol architectureTS

Figure 10: Interactions between RRC and lower layers

The RRC protocol controls and signals the allocation of radio resources to the UE. RRC allows MAC to arbitrate between users and Radio Bearers within the radio resource allocation. The RRC uses the measurements done by the lower layers to determine which radio resources that are available. Therefore it is a need for a measurement report from the UE RRC to the UTRAN RRC. Figure 10 illustrates the principle. The local control and local measurements reporting is handled through the control SAPs between RRC and the lower layers.