lowing cyclic generator polynomials generate these parity bits: gCRC24 D+1, (4.60) gCRC16 (4.61) gCRC12 (4.62) g CRC8 = (4.63) In relation with Figure 4.49 and [10], we denote the bits in a transport block delivered to layer 1 by and the parity bits by PimPim2PimPimL where Aj is the length of a transport block of TrCH i, m is the transport block number, and L is either 24, 16, 12, 8, or 0 depending on what the uppers layers signal. Then en- coding follows systematically; which means that in GF(2) we express the above poly- nomials as: (4.64) The UMTS Network and Radio Access Technology (4.65) (4.66) (4.67) The preceding polynomials yield a remainder equal to 0 when divided by gCRC24(D), gCRC16(D), gCRC12(D), and gCRC8(D), respectively. In the absence of transport block in- puts to the CRC calculation (Mi = 0), CRC attachment does not occur. However, if transport blocks inputs exist in the CRC calculation (i.e. M # 0), and the size of a trans- port block equals zero (A = 0), CRC attachment occurs, i.e. all parity bits equal to zero. Denoting the bits after CRC attachment by where B=A;+Lj; the relation between aimk and bimk can be defined as aimk where k = 1,2,3,...,A; (4.68) bimk = Pim(L,+1-(k-A)) where 1, A + 2, A + 3, A + L. (4.69) 4.6.2 Transport Block Concatenation and Code Block Segmentation All transport blocks in a Transmission Time Interval (TTI) have serial concatenation. When the number of bits in a TTI is larger than Z, i.e. the maximum size of a code block in question, then code block segmentation takes place after the concatenation of the transport blocks. The maximum size of the code blocks depends on whether convo- lutional coding, turbo coding or no coding occurs. We denote the bits input to the transport block concatenation, where i is the TrCH number, m is the transport block number, and Bi is the number of bits in each block (including CRC). M represents the number of transport blocks on TrCH i. denotes the bits after concatenation, where i is the TrCH number and X = MBi. Then, the following rel