5G-Issue: C-V2X( Cellular Vehicle-to-everything)
From 5G issues, there are three kinds of scenarios. The first is eMBB (Enhanced Mobile Broadband), Second is mMTC(Massive Machine type communication ), and last is uRLLC(Ultra-reliable and low latency communications ).
C-V2X is the key to uRLLC technology, and it was proposed by 3GPP standard. Cellular vehicle-to-everything (C-V2X) will serve as the foundation for vehicles to communicate with each other and everything around them. Furthermore, C-V2X is an alternative to 802.11p, the IEEE specified standard for V2V and other forms of V2X communications. Pre-commercial C-V2X deployments have recently gained considerable momentum with support from multiple automakers.
C-V2X provided four application scenarios: V2V(vehicle to vehicle), V2I （vehicle to infrastructure ), V2P （vehicle to vehicle pedestrian ), V2N （vehicle to vehicle network）
V2V(vehicle to vehicle)：Allows vehicles to talk to each other and send and receive, for example, warnings about hard emergency breaking or stationary vehicles to avoid rear-end crashes, as well as collision warnings at traffic turns and intersections to improve traffic safety.
V2I （vehicle to infrastructure )：Allows vehicles to talk to road infrastructure, such as traffic lights, speed signs and toll stations. For example, where drivers can monitor the status and change time of traffic lights, they can anticipate when to slow and accelerate. This not only improves traffic flow and prevents accidents, but also saves fuel and reduces air pollution.
V2P （vehicle to vehicle pedestrian )：Allows vehicles to talk to pedestrians and cyclists via their phones. The purpose of V2P is to protect vulnerable road users, reducing collisions and making streets safer not just for drivers, but for all traffic participants.
V2N （vehicle to vehicle network）： Allows vehicles to talk to the mobile network, enabling highly reliable, longer-range communications between vehicles, infrastructure and pedestrians by using existing cellular infrastructure. Enabling vehicles to communicate beyond line of sight further increases safety on the road and traffic efficiency.
Next, we discuss why C-V2X its techniques are better than 802.11p
802.11p based / DSRC（Dedicated Short Range Communications; 專用短程通信技術), there are some advantages below:
- Both of them used 5.9G Hz, but 802.11p used low BW, and C-V2X used low and high BW(bandwidth) at the same time for high data capacity.
2. At crowded scenario, C-V2X its efficiency is better than 802.11p/DSRC.
3. 802.11p/DSRC has the higher interference influence.
4. Low-cost efficiency: C-V2X can directly combine with a cellular chip.
5. C-V2X can achieve 500km/h in different channel (take Doppler, shading, frequency, time into account), but 802.11p/DSRC has no this requirement or can not be predicted, so the security is unreliable. Higher mobility is reliable, but 802.11p/DSRC will be shading.
News: Europe Union decide 5G and WiFi coexist with each other, 802.11p/DSRC will be supporting character. (2019/07/04 News)
References
- Why Europe just boosted 5G over Wi-Fi for connected cars. VentureBeat, 2019/7/5 CONNECTED VEHICLES: C-V2X on the road to 5G. GSMA.
- 5G could make self-driving cars smarter and commutes safer. CNet, 2019/8/27.
- https://iknow.stpi.narl.org.tw/Post/Read.aspx?PostID=14432
- https://www.qualcomm.com/invention/5g/cellular-v2x
- C-V2X while paper from Qualcomm:https://www.qualcomm.com/documents/path-5g-cellular-vehicle-everything-c-v2x
