adio Access Technology 4.3.9.10 CPCH Status Indicator Channel (CSICH) The CPCH Status Indicator Channel (CSICH) is also a fixed rate (SF=256) physical channel carrying CPCH status information. It has always association with a physical channel used for transmitting a CPCH AP-AICH and uses the same channelization and scrambling codes. Figure 4.29 illustrates the CSICH frame structure. It consists of 15 consecutive access slots (AS) each 40 bits long and having two parts, i.e. one of dura- tion 4096 chips without transmission, and a Status Indicator (SI) part consisting of 8 bits bgi ,b8i+7, where i is the access slot number. The CSICH uses the same modula- tion of the PICH, and has the primary CPICH phase as reference. 4096 chips SI part Transmission off b8i+1 b8i+6 b8i+7 AS #14 AS #0 AS #1 AS #i AS #14 AS #0 20 ms Figure 4.29 Structure of CPCH Status Indicator Channel (CSICH). Each CSICH frame transmits N status indicators {SI SIN-1}, i.e. all the access slots of the CSICH frame transmit status indicator even if some signatures and/or access slots are shared between CPCH and RACH. The mapping from {SI, to the CSICH bits {b0,...,b119} follows Table 4.29. In the event of transmit diversity for the CSICH, STTD encoding applies on the CSICH bits. Table 4.29 Mapping of Status Indicators (SI) to CSICH Bits Number of SI per SIn 1 SIn=0 frame (N) {b0,...,b119}={0,0,...,0} N = 3 {b40n...,b4on+39}={1,1,...,1} N = 5 {b2An....,b2An+23}={0,0,...,0 N = 15 N = 30 {b4n...,b4n+3} {0,0,0,0} N = 60 {b2n,b2n+1} {1,1} {b2n,b2n+1} {0,0} Higher layers set the Status Indicator values for UTRAN. Thus, the higher layers pro- vide Layer 1 with the mapping between the values of the status indicators and the avail- ability of CPCH resources. At the UE the number of status indicators per frame is also a higher layer parameter. 4.3.10 Mapping Transport Channels onto Physical Channels Table 4.30 summarizes the mapping of transport channels onto physical channels. The DCHs are coded and multiplexed as described in [3], and the resulting data stre