ansform precoding is then performed with MPSSCH and MPSSCH parameters followed by precoding for single antenna port transmission. The block of complex-valued modulated symbols z(0), z(M'symb are power-adjusted using the scaling factor BPSSCH and sequentially mapped to PRBs on antenna port p starting with z(0) allocated for PSSCH transmission. The resource elements (k, 1) used for the latter frequency-first mapping should not be designated for transmission of reference signals, start- ing with the first slot in the subframe. Resource elements in the last SC-FDMA symbol within a subframe are counted in the mapping process but not used for transmission. If sidelink fre- quency hopping is disabled, the set of PRBs used for transmission is given by NPRB = N'VRB' where N'VRB is given in [3]. If sidelink frequency hopping with predefined hopping pattern is enabled, the set of PRBs used for transmission is given by the SCI associated with a prede- fined pattern such that only inter-subframe hopping is used. The number of subbands Nsb E {1, 2, 4} is configured by RRC signaling. The parameters E {0, ., 110} is given higher layers; ns = PPSSCH where PSSCH is given in [3]; and CURRENT_TX_NB The pseudo-random sequence generator is initialized at the start of each slot with NSS and the initialization value Cinit E {0, 1, 503,510} is determined by hoppingParameter-r12 RRC parameter; the quantity NVRB is replaced by N'VRB; and for sidelink transmission mode 1, = NSL for sidelink transmission mode 2, NUL = MPSSCH_RP where in given Vehicle-to-Everything (V2X) Communications 825 in [5]; the quantity NPRB is replaced by N'PRB; and the physical RB to use for transmission in [3]. 7.4.2.2 Physical Sidelink Control Channel As we mentioned earlier, the SCI messages are transmitted over PSCCH in LTE-based side- link communication. The fields defined in the SCI formats below are mapped to the infor- mation bits ao to aA-1 such that each field is mapped in the order in which it appears in the description, with the first field mapped to the 