UMTS Radio access

Wide band CDMA (WCDMA) technology was selected to for UTRAN air interface. UMTS WCDMA is a Direct Sequence CDMA system where user data is multiplied with quasi-random bits derived from WCDMA spreading codes. In UMTS, in addition to channelisation, codes are used for synchronisation and scrambling. WCDMA has two basic modes of operation: Frequency Division Duplex (FDD) and Time Division Duplex (TDD).

The functions of Node-B are:

Air interface Transmission / Reception Modulation / Demodulation CDMA Physical Channel coding Micro Diversity Error Handing Closed loop power control

The functions of RNC are:

Radio Resource Control Admission Control Channel Allocation Power Control Settings Handover Control Macro Diversity Ciphering Segmentation / Reassembly Broadcast Signalling Open Loop Power Control