What is 5G New Radio (5G-NR), and how does it relate to the existing 4G architecture?

5G-NR is the new radio technology for 5G that introduces mmWave frequencies and improved air interface, initially deployed as an upgrade to the radio access while reusing the 4G Evolved Packet Core (EPC) — called NSA (Non-Standalone) mode.

* NSA keeps the 4G EPC behind the new 5G radio; SA swaps in a cloud-native 5G Core (5GC). *

What 5G-NR brings:

• New radio technology — a completely new air interface (not backwards compatible with LTE)
• mmWave support — millimeter wave frequencies (24-100 GHz) for extremely high bandwidth but short range
• Improved air interface — better spectral efficiency, lower latency, massive MIMO (many antennas)

Deployment strategy (NSA — Non-Standalone):

5G-NR radio → existing 4G EPC (MME, HSS, S-GW, P-GW) → Internet

• The first phase of 5G deployment reuses the existing 4G core network
• Only the radio access is upgraded to 5G-NR (new gNodeB base stations)
• This is called NSA (Non-Standalone) — 5G radio, 4G core
• Allows faster rollout — operators don't need to build a new core network immediately

Standalone 5G (SA) — the full vision:

• Replaces the 4G EPC with a new 5G Core (5GC) — fully cloud-native, service-based architecture
• Enables the full 5G feature set: network slicing, ultra-low latency (URLLC), massive IoT
• Being gradually deployed as operators upgrade their core networks

Tip: If your phone shows "5G" but speeds seem similar to 4G, you're likely on NSA — the 5G radio with 4G core. True SA 5G with the new core is what unlocks the revolutionary capabilities.

Go deeper:

• 4G EPC vs 5G Core — what actually changes (TelcoLearn) — explains why NSA can reuse the 4G EPC and what the new 5GC's service-based core adds, which is exactly the NSA-vs-SA distinction this card hinges on.
• 5G NR (Wikipedia) — the new air interface, mmWave bands, and the NSA-vs-SA deployment options in one place (and feeds the carousel's 5G-NR diagrams).