Section: 5.5.1 Generation of the reference signal sequence
Content: Reference signal sequence is defined by a cyclic shift of a base sequence according to where - is the length of the reference signal sequence, , is defined in clause 5.5.2.1.2, and, - when either - the higher-layer parameter ul-DMRS-IFDMA is set and the most recent uplink-related DCI contains the Cyclic Shift Field mapping table for DMRS bit field which is set to 1 to indicate the use of Table 5.5.2.1.1-3, or, - the Cyclic Shift Field mapping table for DMRS bit is set to 1 in the most recent uplink-related DCI format 7 which indicates the use of Table 5.5.2.1.1-4, and - otherwise. Multiple reference signal sequences are defined from a single base sequence through different values of . Base sequences are divided into groups, where is the group number and is the base sequence number within the group, such that each group contains one base sequence () of each length , and two base sequences () of each length , . The sequence group number and the number within the group may vary in time as described in clauses 5.5.1.3 and 5.5.1.4, respectively. The definition of the base sequence depends on the sequence length.