 layer offers the transport of data to the higher layer. The characteristics of the physical transport need to be described. When information is transmitted between the RNC and the UE, the physical medium changes. Between the RNC and Node B, where the interface lub is discussed, the transport of information is physically organised in so-called frames. Between Node B and the UE, where the WCDMA radio interface Uu is found, the physical transmis- sion is described by physical channels. A physical channel is defined by the carrier frequency number (UARFCN) and the spreading code (SC) in the FDD mode. Primary Synchronisation Channel (P-SCH) The P-SCH uses the first 256 chips of every timeslot. In a P-SCH a primary synchronisation code is transmitted. This is done in every UMTS cell in every timeslot. If the UE detects the P-SCH it has performed chip synchronisation. The P-SCH (as well as the secondary (S)-SCH) is not transmitted under the cell scrambling code, but uses its own predefined code, which is the same for all cells in the UMTS network. Secondary Synchronisation Channel (S-SCH) The S-SCH also uses only the first 256 chips of a timeslot. In an S-SCH the secondary synchronisation code is transmitted. There are 16 different secondary synchronisation codes that are organised into 64 different combinations. The 64 combinations are grouped with 64 scrambling code groups, each consisting of 8 scrambling codes. Common Pilot Indication Channel (CPICH) CPICH carries a predefined bit/symbol sequence at a fixed rate (15 kbps, SF = 256). It is used for channel estimation and for measurement of the neighbour cells. It is also used in an initial cell search to find the correct scrambling code of a cell. It is also used as the phase reference for most physical channels. Primary Common Control Physical Channel (PCCPCH) PCCPCH is the physical channel that carries broadcast channel (BCH) information. It is a fixed rate channel without power control because it must be decoded by all the mobiles in the cell. The channeli- sation