[10]. The UMTS Network and Radio Access Technology When compressed mode by puncturing and fixed positions occurs, DTX get inserted until N'data,*, bits, because the exact room for the gap is already reserved thanks to the earlier insertion of the p bits. Thus, R is defined as R = N'data.,/P. (4.89) If compressed mode by SF reduction and by higher layer scheduling occurs, additional DTX get inserted when the transmission time reduction method does not exactly create a transmission gap of the desired Transmission Gap Length (TGL). The number of bits available to the CCTrCH in one radio frame of this compressed mode gets denoted by Nane data,* and R=N The exact value of Ndan is dependent on the TGL and the transmission time reduction method signalled from higher layers. For transmission time reduction by SF/2 method in compressed mode and for other methods it can be calculated as For every transmission time reduction method Ndata. = where N'datal and N'data2 are the number of bits in the data fields of a slot for slot format A or B as defined in [1]. NTGL is the number of bits that are located within the transmission gap and defined as: if Nam + TGL < 15, in first frame if N first + TGL > 15, in second frame if N first TGL 15. Nfirst and TGL are part of the description of the compressed mode section. Furthermore, notice that in compressed mode by SF/2 method, we also add DTX in the physical channel mapping stage. During the 2nd DTX insertion the number of CCTrCH bits remains the same as in the normal mode. We denote the bits output from the DTX insertion block by W1, W2, W3,..., W(PR) . Notice also that these bits have four values in case The UTRA Physical Layer Design of compressed mode by puncturing, and three otherwise. We can define them by the following relations: "k=Sky k=1,2,3,...,S and Wk=8,k=S+1,S+2,S+3,...,PR (4.90) where DTX indication bits are denoted by 8. Here Sk E{0,1,p}and & E {0,1} [10]. 4.6.10 Physical Channel Segmentation When using more than one PhCH, the physical channel segmentation event divid