rst rather than frequency-first mapping is applied, where Cmux 2 For SL-BCH configured by higher layers for V2X sidelink, The entire TB containing the sidelink broadcast channel is used to calculate the 16-bit CRC. Information bits inclusive of the attached 16-bit CRC are encoded using tail biting convolutional code (i.e., a TBCC with constraint length 7 and coding rate 1/3) and rate matched. The block of bits b(0), , b(Nbit -1), where Nbit is the number of bits transmitted on the PSBCH in one subframe, are scrambled SO that the scrambling sequence generator is initial- ized at the start of every PSBCH subframe with Cinit = NSL and then QPSK-modulated. Layer mapping with single antenna port and transform precoding are performed on Figure 7.25 Physical sidelink broadcast channel processing [4]. Vehicle-to-Everything (V2X) Communications 829 complex-valued modulated symbols. Transform precoding is performed similar to LTE uplink with parameters MPSBCH RB and MPSBCH SC For transmission on a single antenna port, pre- coding is defined by where i = 0, 1, Mayer symb - 1 and y(0) (i) denotes the transform-precoded complex-valued symbols. The block of complex-valued symbols z(0) z(MP symb 1) are multiplied by an amplitude scaling factor BPSBCH in order to adjust the transmit power, and sequentially mapped to PRBs on antenna port p. The PSBCH uti- lizes the same set of RBs as the synchronization signal. The frequency-first mapping to the PRBs would avoid resources designated for transmission of reference signals or synchroni- zation signals, starting with the first slot in the subframe. The resource element index k is determined by k=k-36 + NSLNRB/2, k' 0, 1, ..,71 since the last symbol of the sub- frame is used as a gap and not used for transmission. 7.4.3 Sidelink Physical Signals 7.4.3.1 Demodulation Reference Signals In LTE V2X, the DM-RSs associated with PSSCH, PSCCH, PSDCH, and PSBCH are trans- mitted similar to LTE PUSCH with different parameters and antenna ports. The set of phys- ical RBs used in the mapping proc