Proximity Services
Also known as: ProSe
Definition
The 3GPP-defined framework of service capabilities — device discovery, direct device-to-device communication, and UE-to-network relay — built on sidelink communications, enabling devices in physical proximity to interact directly without requiring network-mediated connections.
Key Points
- Encompasses several distinct capabilities: proximity discovery (identifying other devices nearby), direct communication (exchanging data over sidelink), and UE-to-network relay for out-of-coverage devices
- Originally developed with public safety use cases as a primary driver, where direct device discovery and communication in coverage-denied or infrastructure-damaged scenarios has clear operational value
- Discovery can operate in different modes depending on whether device proximity information is coordinated through the network or determined entirely through direct device-to-device signaling
- Forms the service-layer framework that specific sidelink applications — relay UE functionality, vehicle-to-everything communication, direct public-safety messaging — are built against, rather than being a single application itself
- Adoption and use case scope has broadened significantly beyond its original public-safety focus as sidelink technology has matured across successive 3GPP releases
Concept
ProSe defines the service-layer procedures that sit above the sidelink radio technology itself — how a device discovers other nearby devices capable of direct communication, how a direct communication session is established and maintained, and how a relay-capable device advertises and provides connectivity extension to out-of-coverage devices. Sidelink provides the radio transport; ProSe defines what devices do with that transport at the service level.
Explainer
The framework structure of ProSe — separating discovery, direct communication, and relay into distinct but related service capabilities — reflects the reality that these functions serve genuinely different operational needs even though they share the same underlying sidelink transport: a device may want to discover nearby peers without necessarily communicating with all of them, or may want to communicate directly with a known peer without needing discovery at all, or may need relay capability specifically because it has no other coverage option. This modularity is why ProSe has extended well beyond its original public-safety motivation into broader use cases like vehicle-to-everything communication and industrial device coordination, since the same underlying service capabilities apply regardless of which specific application is built on top of them. For CE verticals, ProSe-based direct communication capability is most valuable in exactly the environments where relying solely on network-mediated connectivity introduces risk or limitation — coordinating personnel, vehicles, or equipment in remote or coverage-constrained industrial sites, where direct device discovery and communication provides a functional layer of coordination independent of whether full network coverage is present at every point in the operation.
Cite this entry
Proximity Services. ConnectedEarth Knowledge Base. https://connectedearth.space/knowledge-base/proximity-services/ (updated 13 September 2026).