NRSidelink: 3GPP 5G NR Sidelink (PC5) & Satellite Cooperative Relay

NRSidelink specifies 3GPP Release 17/18 NR Sidelink over the PC5 interface, enabling direct device-to-device discovery, public safety communications, and cooperative non-terrestrial satellite relaying without cell tower infrastructure.

NRSidelink PC5 Direct Communications & NTN Satellite Anchor

Mode 2 autonomous distributed resource allocation with satellite synchronization

Central System: Emergency Responder Terminal A - Standard 5G smartphone transmitting on PC5 sidelink

Network Nodes

Emergency Responder Terminal A
Emergency Responder Terminal B
Vehicle-to-Everything (V2X) Gateway
LEO Direct-to-Device Satellite

Architectural Protocol Layers

Spaceborne PHY/MAC Layer (3GPP Rel-17 TS 38.300): Doppler compensation, HARQ disabling, and timing advance extension.
Orbital Mesh Routing (CCSDS / Delay-Tolerant Networking): Dynamic topology routing over intermittent laser crosslinks.
Regenerative Core Processing (OpenRAN / 3GPP CU-DU Split): Onboard user plane function (UPF) local breakout.

Key Metrics: < 18ms (LEO Orbit-to-Ground Roundtrip) | 100 Gbps (Optical Crosslink Throughput) | ±48 kHz (Doppler Shift Compensation) | 99.999% (Orbital Constellation Availability)

3GPP 5G NR Sidelink (PC5), Direct Device-to-Device (D2D) & Satellite Augmentation

Core Engineering Areas

PC5 Mode 2 Autonomous Sidelink Resource Allocation — Core engineering and protocols for PC5 Mode 2 Autonomous Sidelink Resource Allocation.
3GPP ProSe UE-to-Network Relay via Satellite — Core engineering and protocols for 3GPP ProSe UE-to-Network Relay via Satellite.
Direct Sidelink Discovery & Ephemeral Content Caching — Core engineering and protocols for Direct Sidelink Discovery & Ephemeral Content Caching.

Technical Articles

Related Cluster Architecture Specifications

NonTerrestrialNetwork — 3GPP 5G/6G NTN Satellite Architecture, Direct-to-Cell & Non-Terrestrial Infrastructure
NonTerrestrialNetworks — Multi-Orbit Heterogeneous Constellation Interworking (LEO / MEO / GEO / HAPS)
AirspaceSync — Doppler Compensation, Relativistic Timing & Airspace-Space Synchronization
FSOComm — Free Space Optics, High-Bandwidth Space Laser Communications & Atmospheric Mitigation