bits for each TrCH in the radio frame. We denote the bits from rate matching by The UTRA Physical Layer Design where Gi is the number of bits in one TTI of TrCH i. Likewise, we denote the number of bits in one radio frame of TrCH i by H. Finally, we also denote by Di the number of bits output of the first DTX insertion block. In normal or compressed mode using spreading factor reduction, Hi is constant and cor- responds to the maximum number of bits from TrCH i in one radio frame for any trans- port format of TrCH I, and Di = Fi X H Within compressed mode using puncturing techniques, additional puncturing occurs in the rate matching block. The empty positions resulting from the additional puncturing get p bits inserted in the first interleaving block, the DTX insertion is thus limited to allow later insertion of p bits. Consequently, DTX bits get inserted until the total num- ber of bits is Di where: D = and (4.84) We denote the output bits from the DTX insertion by where these three valued bits can be expressed by following relations: (4.85) hik=8, k=G,+1,G+2,G+3,..,D (4.86) where we denote DTX indication bits by 8. Here gik E {0,1} and 8 E {0,1}. 4.6.9.2 Second Insertion of DTX Indication Bits The DTX indication bits inserted in the 2nd insertion get placed at the end of the radio frame, and the DTX will be distributed over all slots after 2nd interleaving. The input bits to the DTX insertion block get denoted by S1,S23S33...,SS where S is the number of bits from TrCH multiplexing. We denote by P the number of PhCHs and the number of bits in one radio frame, including DTX indication bits, for each PhCH by R. In a normal (4.87) where Ndatal and Ndata2 are defined in the first part of this chapter and [1]. For com- pressed mode, N'data,* is defined as N data.* = (4.88) where N datal and N'data2 are the number of bits in the data fields of the slot format used for the current compressed mode, i.e. slot format A or B as defined in [1] corresponding to the spreading factor and the number of transmitted slots in use 