V2X

V2X is the umbrella for vehicles talking to everything around them — other vehicles (V2V), roadside infrastructure (V2I), pedestrians' devices (V2P), and the network/cloud (V2N). The goal is safety and coordination: a car can warn the one behind it of hard braking, get signal-phase timing from a junction, or join a platoon, with the kind of low latency and reliability that matters when the payload is a collision warning.

The detail worth knowing is that V2X runs over two distinct paths. PC5 is the direct sidelink — devices talking to each other directly, no base station in between, which is what you want for low-latency, local safety messages that must work even outside network coverage. Uu is the normal link through the network, better suited to less time-critical, wide-area information like traffic and infotainment. NR V2X (building on earlier LTE C-V2X) extends this toward the demanding stuff — platooning, sensor sharing, autonomous driving — that needs tighter latency and reliability than the first wave of basic safety messaging.