s to the MSB of the RNTI binary value, resulting in the sequence of bits C1,..., CK-1 where = bk = 0, 1, NDCI + 7 and Ck = [bk ++XRNTI(k) - NDCI - 8)]mod 2AK = NDCI = + 8, NDCI + 9,..., NDCI + 23 [6,7]. The PDCCH encoding stages are shown in Fig. 4.15. The K scrambled information bits are delivered to the channel coding block and are polar coded, by setting the encoder para- meters to the following nmax = 9,I = 1, NPC = 0, and nwm=0. The encoding process pro- duces N bits which are denoted as do, d1,..., dN-1. The rate matching for polar coded bits is performed on per coded block and consists of subblock interleaving, bit collection, and bit interleaving. Detailed PDCCH channel encoding and decoding block diagram is shown in Fig. 4.16. New Radio Access Physical Layer Aspects (Part 2) 445 Determination Determination of encoded of RNTI bit length DCI bits sequence Ones-initialized Frozen bit Subblock CRC24C attachment Polar encoding Rate matching Multiplexing generation padding scrambling interleaving insertion interleaving onto PDCCH PDCCH encoding procedure Determination Determination of of RNTI information block length Subblock DCI bit sequence extraction Distributed CRC-aided successive cancellation list polar decoding Demultiplexing deinterleaving dematching from PDCCH PDCCH decoding procedure Figure 4.16 NR PDCCH channel encoding/decoding block diagram [7,35]. No puncturing or shortening Puncturing Shotening Repetition Start Subblock Circular Bit-level Polar encoding interleaving buffer interleaving Figure 4.17 Encoding of NR PDCCH and rate matching variants [68]. The input bit sequence to rate matching function is denoted by do, d1 ., dN- and the out- put is denoted by fo,f1,...,FE-1. The input bits to the subblock interleaver are divided into 32 subblocks and the output bits are generated according to yn = dJ(n) where J(n) = mod N/32) An=0,1, ., N - 1 and the subblock interleaver pattern is defined in [7]. The repetition, puncturing, or shortening of polar code is per- formed in the following manner: N = 2n