\brief This function generates the downlink reference signal for the PUSCH according to 36.211 v8.6.0. The DRS occuies the RS defined by rb_alloc and the symbols 2 and 8 for extended CP and 3 and 10 for normal CP.
\brief This function initializes the Group Hopping, Sequence Hopping and nPRS sequences for PUCCH/PUSCH according to 36.211 v8.6.0. It should be called after configuration of UE (reception of SIB2/3) and initial configuration of eNB (or after reconfiguration of cell-specific parameters).