nal Turbo LDPC/Polar Retransmission Waveform SC-FDM Scheduling CSMA-CA SPS + relative energy based Channel width 10 or 20 MHz Flexible 358 Open Radio Access Network (O-RAN) Systems Architecture and Design ITS Protocol Stack Safety Application Layer Facilities Layer Wave Short Message Protocol (WMSP) 802.11p LTE C-V2X 5G/NR C-V2X Modem Modem Modem PDCP/SDAP MAC ext, LLC MAC/RLC MAC/RLC Viterbi Turbo/Viterbi Polar/LDPC SC-FDMA CP-OFDM FIGURE 11-6 V2X protocol stacks. V2X, vehicle-to-anything. The different wireless protocol stacks all communicate to the ITS protocol stack through the common Wave Short Message Protocol (WMSG) layer as is shown in Fig. 11-6. Deployment timeline Car makers are starting to introduce V2V communication in their vehicles. Toyota announced plans to begin broad deployment IEEE 802.11p vehicles from 2021. Cadillac (General Motors Group) is using IEEE 802.11p. Volkswagen enables V2X through IEEE 802.11p since 2019. Ford announced plans to enable C-V2X in partnership with Qualcomm in October 2017, but this is not commercially deployed. Overall, given the limited number of equipped vehicles, lack of harmonization, and lim- ited roadside infrastructure, there is currently no single "winning" standard for V2X commu- nication. Note that C-V2X and 802.11p can coexist if they are on adjacent/near-adjacent channels, allowing dual-mode roadside unit (RSU) to be built. Roadside unit The purpose of the RSU is to provide the infrastructure side of the V2I communication link. This includes both a communication function (V2I/V2X communications) and the intelli- gence/decision-making function to interpret received messages and generate the appropriate messages to be transmitted. Chapter 11 Differentiation by use case Traditional RSU Hardware Unit LTE/5G Modem Ethernet expansion FIGURE 11-7 Roadside unit overview. System architecture A typical implementation of a traditional RSU hardware is shown in Fig. 11-7. In this unit, the V2X modem itself is typically a modem, intended for vehicular use, that is repurp