 stage, initialization based on Cell ID, the sequence is partitioned into four non-overlapping portions. The portion for transmission is selected based on the second and third least significant bits of the SFN. In the second scrambling stage, initialization based on Cell ID, the sequence is partitioned into four or eight non-overlapping portions. The portion for transmission is selected based on the second or third least significant bits of the SS block time index. The physical layer processing of the PBCH is shown in Fig. 4.9. We denote the MIB bits in a TB delivered to the physical layer by ao, a1,..., ANMIB-1' where NMIB = 32 bits is the payload size of the MIB. The lowest order information bit ao is mapped to the most significant bit of the TB payload. Additional timing-related PBCH payload bits ANMIB+7 regen- erated based on the least significant bits of the SFN, half frame, SS block index, and com- bined with the MIB payload (see Fig. 4.10). The NMIB + 8 bits are interleaved according to an interleaving pattern specified in [7] prior to the first scrambling stage. In the first scrambling Chapter 4 BCH Data NMIB-1' 4th, 3rd, 2nd, and the 1st LSB of SFN Half radio frame bit if Lssg = 64 6th, 5th, and 4th bits of SS/PBCH block index ANMIB+5 =5th and 4th bits of SS/PBCH block index Interleaving Figure 4.10 NR PBCH payload generation [7]. stage, the input bits to the scrambling unit ai are scrambled according to = = 0, 1, ,NMIB + 7 where Si is a sequence that is derived from a generic pseudo-random length-31 Gold sequence, which is initialized with Cinit = Ncell at start of each SFN whose value satisfies SFN mod 8 = 0 The Si further depends on the half radio frame index, and the second and third least significant bits of the system frame number [7]. A CRC is calculated for the purpose of error detection on the entire BCH payload. The input bit sequence is denoted by and the parity bits by P0,P1,..., where A = NMIB + 8 is the payload size and L = 24 is the number of CRC parity bits. The parity bits are calculated