# Evolution of V2X Communication and Integration of Blockchain for Security Enhancements
## 3 Evolution of V2X Technologies
### Evolution of Cellular V2X
#### 3.2.1 Evolution from Lte-V2X to 5G NR V2X  
In 2016, the 3 GPP achieved the first cellular V2X standard called LTE-V2X with Rel.14 [31]. Since then, every subsequent release has been further improved. Similar to the evolution of 3G and 4G; the 5G \begin{table}
\begin{tabular}{l l l} \hline \hline
**Features** & **LTE** & **5G NR** \\ \hline Frequency band & Up to 6 GHz & \begin{tabular}{l} Up to 5.9 GHz; \\ mmWave (upto 52 GHz) \\ \end{tabular} \\ \hline PHY layer & SC-FDMA & SC-FDMA, OFDM \\ \hline Carrier aggregation & Up to 32 & Up to 16 \\ \hline Digital beamforming & Up to 8 layers & Up to 12 layers \\ \hline Channel coding & \
\begin{tabular}{l} Data: Turbo coding \\ Control: Convolution coding \\ \end{tabular} &
\begin{tabular}{l} Data: LDPC coding \\ Control: Polar coding \\ \end{tabular} \\ \hline MCS & QPSK, 16-QAM & QPSK, 16-QAM, 64-QAM \\ \hline Control \& data multiplexing & FDM & TDM \\ \hline Scheduling interval & One sub-frame & Slot, mini-slot or multi-slot \\ \hline Side link modes & Modes 3 and 4 & Modes 1 and 2 \\ \hline Spectrum occupancy & Up to 90\% of channel BW & Up to 98\% of channel BW \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Summary of advancement in 5G NR over 4G LTE. NR evolution is part of the ongoing mobile network development process to satisfy the demands of 5G technologies as shown in Figure 5. The central goal of 5G NR evolution is to improve mobile broadband so it is equivalent to a wired infrastructure in terms of low cost, high bandwidth, high performance, and extremely low latency, which can offer faster, highly efficient, and time-critical services. In 2016, an alliance known as 5G Automotive Association (5 GAA) was established by the global industries from automobile, telecom, and IT industries. It is a cross-industry, multinational alliance, which describes the C-V2X platform and its evolution to 5G. The 5 GAA goal is to demonstrate the long-term promise of C-V2X capability and provide superior performance and ever-increasing capabilities based on 3 GPP cellular technology. Moreover, 5 GAA promotes 5G connectivity solutions that help to increase global market penetration, availability, and that facilitate C-V2X standardization. In March 2017, the 3 GPP worked on specialization of C-V2X in Rel.14. Before Rel.15, the 3 GPP worked on developing the functionality of LTE in PC5 direct communication and LTE-Uu interfaces. In 2018, 3 GPP continued working on the initial standardization process of New Radio for 5G network, as a first step in Rel.15. In June 2018, the 3 GPP published the first full 5G NR specification in Rel.15. In 2019, the 3 GPP continued to improve C-V2X and expanded standardization research as well as early testing and implementation of 5G NR in Rel.16. Similarly, in Rel.16, 5G NR C-V2X (or 5 NX for short), which is based on Rel.14 C-V2X, will support several communication mechanisms such as unicast, broadcast and geocast. The geocast provides a feedback mechanism for higher reliability. If the signal cannot be interpreted by the system, then NACKs are sent over the same radio resources. When compared to the previous Rel.14 i.e., C-V2X, 5 NX provides additional features, such as coordinated driving or platooning based on PC5 communications and enhanced situational awareness for safer driving. In 2019, the standardization of new 5 NX radio technology in Rel.16, provided adequate requirements and new possibilities for current and future autonomous driving industries, while, at the same time, retaining backward compatibility. Some recent C-V2X communication capabilities include wide-band transmission for precise vehicle coverage and positioning, revolutionary architectures for ultra-low latency slot structure, scalable OFDM technology, massive MIMO support, etc. The 5 NX offers a unifying communication platform for future autonomous vehicles, such as massive IoT, mission critical services, and improved broadband wireless access.