omposite trans- port channels; rate matching; modulation and spreading/demodulation and de-spreading of physical channels; macro-diversity distribution/combining and soft handover execution; mapping of coded composite transport channels on physical channels; power weighting and combining of physical channels; frequency and time (chip, bit, slot, frame) synchronization; measurements and indication to higher layers (e.g. FER, SIR, interference power, transmit power, etc.); closed-loop or fast power control; RF processing; support of uplink synchronization (TDD only); support of timing advance on uplink channels (TDD only). 3.8.3 Services and Functions in Layer 2 3.8.3.1 Services and Functions in The MAC Sub-layer Specification in [12] provide the details of the MAC protocol; here we simply summa- rize the main services and functions. 3.8.3.1.1 Services to upper layers Data transfer provides unacknowledged transfer of MAC SDUs between peer MAC entities without segmentation. Reallocation of radio resources and MAC parameters performs on request of RRC execution of radio resource reallocation and change of MAC parameters. In TDD mode, in addition, the MAC handles resource allocation autonomously. Reporting of measurements reports local measurements, e.g. traffic volume and quality indication to the RRC. The UMTS Network and Radio Access Technology 3.8.3.1.2 Logical channels The MAC layer provides data transfer services on logical channels. We classify these channels in two groups, i.e. control channels for control-plane information transfer, and traffic channels for user-plane information transfer (see Table 3.4). Table 3.4 Summary of Logical Channels Logical channels Description Control Channels (CCH) Broadcast Control Channel (BCCH) Transfer of control plane A downlink channel for broadcasting system control information information only Paging Control Channel (PCCH) A downlink channel transferring paging information. Dedicated Control Channel (DCCH) A point-to-point bi-directional channel that transmits dedicated co