mportant for early termination of decoding process, because the post- CRC interleaver can distribute information and CRC bits such that partial CRC checks can be performed during list decoding and paths failing partial CRC check can be pruned, lead- ing to early termination of decoding. The post-CRC interleaver design is closely tied to the CRC generator polynomial, thus by appropriately selecting the CRC polynomial, one can achieve better early termination gains and maintain acceptable false alarm rate. The signal flow graph of D-CRC polar encoding and decoding is shown in Fig. 4.47. In NR, the polar code is used to encode broadcast channel as well as DCI and uplink control information (UCI). Let us denote by N the number of control bits that must be transmitted using a code of length E bits. We add LCRC CRC bits to the information bits, resulting in K bits that will be encoded by an (N,K) polar encode with N = 2n. Rate matching is per- formed to obtain a code of length E and effective rate R = Nc/E. To each vector (ao, containing Nc control information bits to be transmitted, LCRC-bit CRC is attached. The resulting vector C = (co, CK-1) comprising K = Nc + LCRC Chapter 4 CRC calculation Channel interleaver Rate matching circular Bit interleaver buffer Subchannel allocation Polar encoder Subblock interleaver + PC bits calculation Figure 4.47 3GPP NR polar encoding flow graph [36]. is passed through an interleaver. Based on the desired code rate R and codeword length E, a polar code of length N is utilized along with the relative bit channel reliability sequence and the frozen set. The interleaved vector c' is assigned to the information set along with the PC bits, while the remaining bits in the N-bit vector u are frozen. Vector u is encoded with d = uG, where the generator matrix G was defined earlier. After encoding, a subblock interleaver divides d into 32 equal-length blocks, scrambling them and creating vector y that is fed into the circular buffer as illustrated in Fig. 4.47. For rate matching, puncturing,