How V2X actually works.
Nine pages, in the order an engineer would want them. The radio choice and why it is now effectively settled. The spectrum, band by band, with the real MHz figures. The messages, with their real names and IDs. The layered station architecture that keeps the messages independent of the radio. The antenna and RF chain that decides what range you actually get. The satellite position and time that the radio, the messages and the security checks all lean on. And the silicon. Then the software environment that turns all of it into something a team can actually develop against.
In the order an engineer would want them.
C-V2X
PC5 and Uu, 3GPP Releases 14 through 19, LTE-V2X and NR-V2X, resource allocation modes.
DSRC vs C-V2X
The technical comparison, the measured performance delta, and how the standards war ended.
Spectrum
5.9 GHz allocations in the US, EU, China, Korea, Japan and India, with the real MHz figures.
Message sets
SAE J2735 and the ETSI ITS messages, with IDs and rates.
ITS station architecture
ETSI EN 302 665 — access, networking, facilities, applications, and the two vertical entities.
Antennas and RF
Placement, polarisation, the three antennas in one enclosure, and where the datasheet range goes.
AmbiV2X Developer Stack
The ROS 2 V2X development environment for AmbiOBU and AmbiRSU — Ubuntu, ROS 2 Humble, J2735 and IEEE 1609.x integration, Release 14 C-V2X.
GNSS and time synchronisation
Why C-V2X needs satellite time, how the sidelink falls back without it, and how timestamps and security checks depend on it.
Chipsets and hardware
NXP, Qualcomm, Autotalks, Microchip, Unex, Quectel, and the OBU/RSU platforms.
If you only read two of them.
Read C-V2X first. It is the radio that carries almost all of this, and the distinction between its two interfaces — the direct sidelink and the network path — explains more of the industry's behaviour than any other single fact.
Then read message sets. Interoperability lives at that layer, not at the radio: two devices from two vendors can share a radio and still be mutually useless if they do not agree on the message.
If you are building rather than specifying, the AmbiV2X Developer Stack is where those layers become an actual development environment — and where the boundary between the application middleware and the standards implementation is drawn explicitly.
If you are new to the subject, how V2X works is a better starting point than any page in this section. It covers the same ground without a single standard number.
Adjacent pillars.
V2X use cases
What all of this technology is for, family by family, with the mode and the message set that carry each one.
V2X security
The envelope wrapped around every message on this page, and why it has to verify offline.
V2X regulation
Which of these technologies each jurisdiction has actually permitted.
The V2X market
Who actually ships this silicon in a production vehicle, who supplies it, and who walked away.
Standards
Where to download every specification named in this section, and which cost money.
Building one of these
Turning the architecture on this page into a unit you can fit to a vehicle or a gantry is an engineering programme. That is what Ambimat does.
Last updated 2026-10-01 · Technical reference maintained by Ambimat Electronics, Ahmedabad, India. Corrections: v2x@ambimat.com