Vehicle-to-network — the wide-area half of V2X.
Everything on the PC5 sidelink is local, direct and fast. Everything on Uu — the conventional cellular interface — is wide-area, routed and comparatively slow. V2N is the second half. It cannot support intersection movement assist, and it is the only practical way to deliver a hazard map, a certificate batch, an HD map tile or a firmware image.
Six workloads that have no business on the sidelink.
- Long-horizon hazard information — traffic ahead, incidents, weather, road closures, at a range far beyond any radio horizon
- HD map tile delivery and map change feeds
- Certificate lifecycle — pseudonymous certificate batches pre-fetched from the Authorisation Authority, trust-list and CRL updates. This is the workload most people forget, and it is the one that determines whether a vehicle can still sign messages after a week offline.
- OTA firmware and software update — including the security-relevant update path mandated by UNECE R156
- MEC-assisted services — collective perception aggregated at a multi-access edge compute node, teleoperation backhaul
- Network-assisted sidelink scheduling — in LTE-V2X Mode 3 and NR-V2X Mode 1, the network allocates sidelink resources, which requires coverage
And all six of those need a subscription. Uu is a normal cellular link, which means the vehicle needs a cellular identity that survives fifteen years, several markets and possibly several owners, in a sealed unit with no accessible SIM slot. In practice that means an embedded SIM provisioned remotely under GSMA's SGP.32 IoT specification, not a card someone inserts. It is the least glamorous dependency in a V2X programme and one of the more common ones to underestimate — a certificate batch that cannot be delivered is a vehicle that eventually cannot sign. eSIM and eUICC architecture → · The credential-lifecycle parallel →
Europe's C-Roads deployments are explicitly hybrid, and they are right to be.
C-Roads distinguishes short-range C-ITS (ITS-G5 or PC5) from long-range C-ITS (cellular) and deploys both, with the same message content and the same security envelope crossing either path. That is the correct model: the message set and the security layer are access-agnostic by design in the ETSI ITS station architecture, so a DENM is a DENM whether it arrived over the sidelink from a car 400 metres away or over LTE from a national traffic centre.
Two production services that ship today with no 5.9 GHz radio at all.
Volvo Cars' Hazard Light Alert and Slippery Road Alert launched on the 90 Series in Sweden and Norway in 2016 and went Europe-wide on 15 April 2019, standard on all model-year 2020 Volvos on the SPA and CMA platforms. Volvo publicly invited other manufacturers to pool data, and shares data between Volvo Cars and Volvo Trucks in Sweden and Norway.
Audi's Traffic Light Information, launched in 2016 over LTE with an Audi connect subscription, adds GLOSA from February 2019, and reached more than 22,000 connected intersections in the US by July 2021.
Neither is a substitute for direct V2X, and neither claims to be. Both demonstrate the point that matters commercially: cloud V2X has no penetration problem. It works with one equipped vehicle. That is exactly why it deployed and direct V2V did not. Who ships what →
Where this fits.
C-V2X
PC5 and Uu compared line by line, and why the Uu side needs a subscription.
V2I
The direct-radio counterpart, at millisecond latency.
V2X PKI
The certificate batches Uu delivers, and what happens when it cannot.
AmbiOTA
The update path on the other end of the Uu link.
eSIM and eUICC architecture
The remote provisioning model behind a fifteen-year cellular identity with no SIM slot.
V2D and V2C
Where the cloud path stops being cooperative ITS and becomes telematics.
Questions this page answers.
What is the difference between PC5 and Uu?
PC5 is the direct device-to-device sidelink — vehicle to vehicle, vehicle to roadside unit, vehicle to a pedestrian's handset — with no base station in the path. It works out of coverage and without a subscription. Uu is the standard cellular interface between a device and a base station, requiring network coverage. Safety messaging uses PC5; wide-area services use Uu; a complete deployment uses both.
Does V2N need 5G?
No. V2N works over LTE and is deployed that way in production today. 5G brings lower latency, higher throughput and — with edge compute — the ability to support some of the Release 16 advanced use cases such as teleoperation and high-rate sensor sharing.
Is V2N secure?
The transport is secured by the cellular network's own mechanisms plus TLS to the application server. The V2X messages carried inside are secured by the same IEEE 1609.2 or ETSI TS 103 097 envelope used on the sidelink, so the security model does not change with the access technology.