the TFCI information corresponds to the TFC defined by the The transport format set size is defined as the number of transport formats within the transport format set. The UTRA Physical Layer Design RRC layer to reference the TFC of the CCTrCH in the associated DPCH radio frame. The output code word bits bj are then given by: (4.93) where = =0,...,31, and the output bits are denoted by bk, k = 0,1,2,...,31. In the downlink if the SF < 128, the encoded TFCI code words get repeated yielding 8 encoded TFCI bits per slot in normal mode and 16 encoded TFCI bits per slot in com- pressed mode. 4.6.13.3 TFCI Operation in the Split Mode If one of the DCH has association with a DSCH, the TFCI code word gets split in such a way that the code word relevant for TFCI activity indication is not transmitted from every cell. Higher layer signalling indicates usage of this latter functionality. In this case we encode the TFCI bits using a (16,5) bi-orthogonal (or first order Reed- Muller) code as illustrated in Figure 4.53. Table 4.42 illustrates the code words of the (16,5) bi-orthogonal code, which are linear combinations of 5 basic sequences. If we define a 1st set of TFCI information bits as a1,0,a1,1,a1,2,a1,3,a1,4, where a1,0 = LSB and a1,4 = MSB, we can assume this set of TFCI information bits will correspond to the TFC index ¹5 defined by the RRC layer to reference the TFC of the DCH CCTrCH in the associated DPCH radio frame. Likewise, if we define a 2nd set of TFCI information bits as where a2,0 = LSB and a2,4 = MSB, we can assume that this set of TFCI information bits will correspond to the TFC index defined by the RRC layer to reference the TFC of the associated DSCH CCTrCH in the corresponding PDSCH radio frame. Then, the output code word bits bk are given by [10]: ) mod mod 2, (4.93) where i = 0,...,15, j = 0,1 and the output bits are: bk, k = 0,1,2,...,31. Table 4.41 Basis Sequences for (32,10) TFCI Code [10] 15 Expressed in unsigned binary. The UMTS Network and Radio Access Technology TFCI code (16,5) (5 bits) bi-or