6.2.2 LDPC base graph selection
38.2123GPPMultiplexing and channel codingNRRelease 17TS
For initial transmission of a transport block with coding rate indicated by the MCS index according to Clause 6.1.4.1 in [6, TS 38.214] and subsequent re-transmission of the same transport block, each code block of the transport block is encoded with either LDPC base graph 1 or 2 according to the following:
– if , or if and , or if , LDPC base graph 2 is used;
– otherwise, LDPC base graph 1 is used,
where is the payload size as described in Clause 6.2.1.