ed C = B/(Kcb-LCRC)]. The code blocks are then fed into the channel coding unit. The LDPC encoded bits are denoted by dio, du d(N,-1) where the value of N1 is calculated as follows: If the bit sequence input for a given code block to channel coding is denoted by co, C1,..., CK-1 where K is the number of bits to encode, and the LDPC encoded bits are denoted by do, d1,...,dn-1 then N = 66Z for LDPC base graph 1 and N = 50Z for LDPC base graph 2, where the lifting factor Z is given in Table 4.7 [7]. The NR LDPC base graphs parameters are shown in Table 4.8. The rate matching for LDPC code is performed on code block basis and consists of bit selection and bit-level interleaving. The input bit sequence to rate matching block is denoted as do, d1,..., dn which is written into a circular buffer of length Ncb for code block l, where code length N was defined earlier. Let us assume Ncb = N for the 1th code block, if ILBRM = =07 and in other cases Ncb = min(N, NREF), in which NREF = TBSLBRM/(RLBRMC), C is the number of code blocks of the transport block, RLBRM = 2/3 and TBSLBRM for DL- SCH/PCH is obtained from Table 4.16, taking into consideration the maximum number of layers for one TB supported by the UE in the serving cell; the maximum modulation order Limited-buffer rate matching (LBRM) is a technique to process HARQ with reduced requirements for soft buffer sizes while maintaining the peak data rates. LBRM shortens the length of the virtual circular buffer of the code block segments for certain large sizes of transport blocks, thus sets a lower bound on the code rate. 490 Chapter 4 configured for the serving cell, if configured by higher layers; otherwise, a maximum modu- lation order of Qm = 6 is assumed for DL-SCH; and the maximum coding rate of 948/1024. Due to unequal amplitude of demodulated log likelihood ratios (LLRs) for 16QAM/ 64QAM/256QAM modulated symbols, it is necessary to consider a bit interleaving scheme for high-order modulations (see Fig. 4.37) in order to enhance the performance of the LDPC codes. T