technical specification in [1] describes the primary CCPCH structure with STTD encoding. The UMTS Network and Radio Access Technology 256 chips (Tx OFF) 18 bits Tslot = 2560 chips, 20 bits Slot #0 Slot #1 Slot #i Slot #14 1 radio frame: Tf = 10 ms Figure 4.22 Primary CCPCH frame structure. 4.3.9.3 Secondary Common Control Physical Channel (S-CCPCH) The two CCPCH types, i.e. those that include TFCI and those that do not, carry the FACH and PCH. Since it is the UTRAN which determines when a TFCI shall be trans- mitted, it is mandatory that all UEs support the use of TFCI. Possible secondary CCPCH rates are the same as for the downlink DPCH. Figure 4.23 illustrates a secon- dary CCPCH frame structure, where the parameter k determines the total number of bits per downlink secondary CCPCH slot. It is related to the spreading factor SF (= 256/2*) of the physical channel with spreading range of 256 down to 4. Pilot NTFCI bits Ndata bits Npilot bits Tslot = 2560 chips, 20*2k bits (k=0..6) Slot #0 Slot #1 Slot #i Slot #14 1 radio frame: Tf = 10 ms Figure 4.23 Frame structure for the secondary common control physical channel. Table 4.22 presents the number of bits per field, as well as the channel bit, and symbol rates before spreading for the secondary CCPCH. Table 4.23 illustrates the pilot pat- terns. We can map the FACH and PCH to the same or to separate secondary CCPCHs. If the first case occurs, one frame can serve both. Key characteristics and differences are: A CCPCH does not have inner-loop power control as a downlink dedicated physi- cal channel does. While a transport channel mapped to the primary CCPCH (BCH) can support only a fixed pre-defined transport format combination, a secondary CCPCH can support multiple transport format combinations using TFCI. We can transmit a primary CCPCH over the entire cell. A secondary CCPCH may be transmitted in a narrow lobe in the same way as a dedicated physical channel, only when carrying the FACH. The UTRA Physical Layer Design Table 4.22 Secondary CCPCH Fields Channel bit