ed PRACH resource to the gNB. The gNB then transmits a beam failure recovery response (BFRP) to the UE. 3.5.9 Channel Coding and Modulation In NR, due to the demand for Gbps-level user throughput and lower implementation com- plexity, the conventional Convolution Turbo Codes (CTCs) supported in LTE-A for data channel transmission were replaced by LDPC codes (3GPP TS 38.212). The NR LDPC codes are represented by a special parity check matrix that has a quasi-cyclic structure. The parity check matrix can be also represented via a bipartite graph with variable nodes correspond- ing to the columns and check nodes corresponding to the rows of the matrix. If the entry in the parity check matrix has a non-zero element, the corresponding variable and parity nodes in the graph are connected with the edge. 3.5 NR Physical Layer Base graph 2 Base graph 1 Code rate Figure 3.5.18 Code rate and transport block size scenario for LDPC base graphs. LDPC codes are decoded by exchanging information between variables and parity checks inside a graph in an iterative manner, where the messages which are exchanged between nodes represent probability distributions for the associated bits. At each iteration, the mes- sages are further processed and updated at the nodes of the graph. Unlike CTCs in LTE-A, which always decode the received code block under the assumption of the low code rate of 1/3, the design of the NR LDPC codes allows for the decoding of high rate code blocks. In this case, the bits that are not transmitted are not accounted for in the decoding process, thus reducing the complexity of LDPC decoding as the code rate increases. Such LDPC code design makes it easier to support higher data rates with reasonable implementation complexity. The parity check matrix of the NR LDPC codes is defined by a smaller base matrix and each entry of the base matrix represents either a ZxZ zero matrix or a shifted Zx. Z identity matrix. For better performance optimization and improved decoding latency for the sup- ported range of block leng