5G Deployment Options Explained: SA vs NSA and EPC vs 5GC Migration Paths
Exploring 5G Deployment: SA vs. NSA and EPC vs. 5GC Migration Explained
Transitioning from 4G LTE (EPC) to 5G NR (New Radio) and 5GC (5G Core) isn’t something you can just do in one go. Instead, the 3GPP standards present a few deployment options that let operators make the shift at their own pace. These options feature both Standalone (SA) and Non-Standalone (NSA) modes, allowing for various combinations of LTE, NR, EPC, and 5GC.
The image attached gives a quick overview of the key deployment scenarios — Options #1, #2, #3, #4, #5, and #7. Each has its role in how networks adapt based on things like available spectrum, costs, and operators' strategies.
Now, let’s take a closer look at what each of these options means, how they’re different, and what advantages they bring to the table.
Background: EPC vs 5GC
Before we dig into the options, it’s good to clarify two main components in the network:
EPC (Evolved Packet Core) – This is the core network we use with LTE (4G). EPC supports NSA deployments of NR but doesn’t include many advanced features found in 5G.
5GC (5G Core) – It uses a service-based, cloud-native architecture that supports network slicing, URLLC (Ultra-Reliable Low-Latency Communication), and can handle massive IoT.
Standalone (SA) vs Non-Standalone (NSA)
Standalone (SA):
Utilizes just one radio access technology (LTE or NR).
Devices connect straight to the 5GC or EPC using a single RAT.
Offers genuine 5G experiences with NR + 5GC (Option #2).
Non-Standalone (NSA):
Merges LTE and NR simultaneously, where LTE often acts as the anchor for control signaling.
Speeds up the rollout of 5G by taking advantage of existing LTE infrastructure.
Commonly seen in early 5G launches (like Option #3 and Option #7).
The Deployment Options Explained
The attached image shows some practical deployment options for the evolution to 5G. Here’s a closer breakdown:
Option #1: SA LTE under EPC
Description: All about pure LTE with EPC (that’s the old 4G stuff).
Status: Widely used already; doesn’t play into future developments.
Use: Serves as the baseline reference.
Option #2: SA NR under 5GC
Description: Standalone NR (5G radio) directly linked to 5GC.
Advantages:
Brings in real 5G capabilities (like URLLC, mMTC, slicing).
Works independently of LTE.
Deployment: Seen as the end goal for many operators.
Option #3: NSA LTE and NR under EPC
Description: LTE acts as the anchor, with NR boosting capacity and speed.
Advantages:
Quick way to roll out 5G using existing EPC.
Lets operators advertise “5G” even without fully deploying 5GC.
Limitation: Can’t support full 5G services like network slicing.
Example: Frequently used in the first wave of 5G launches worldwide (2019–2021).
Option #4: NSA NR and LTE under 5GC
Description: NR takes the lead with LTE as a supporting role, both running under 5GC.
Advantages:
Takes advantage of 5GC for advanced features.
Sets the stage for a smooth move to SA NR.
Limitation: More complicated compared to Option #3.
Use: A transitional step for operators moving towards full 5G.
Option #5: SA LTE under 5GC
Description: LTE connects to 5GC with no NR involved.
Advantages:
Lets operators switch to 5GC first and add NR later.
Supports features like network slicing on LTE.
Limitation: Still limited by LTE’s air interface.
Use: Handy in areas where NR spectrum isn’t up and running yet.
Option #7: NSA LTE and NR under 5GC
Description: Both LTE and NR connect to 5GC, working together in NSA mode.
Advantages:
Supports dual connectivity and takes full advantage of 5GC.
Balances LTE coverage with NR’s capacity and performance.
Limitation: Integration is trickier compared to Option #3.
Use: Popular where LTE is strong, but operators want to roll out NR with 5GC perks.
Comparison of Deployment Options
Here’s a handy reference table for clarity:
Option Mode Core Network Anchor RAT Key BenefitsLimitations#1SAEPCLTELegacy LTE baseline No 5G features#2SA5GCNRTrue 5G (URLLC, slicing)Requires NR rollout#3NSAEPCLTEFast 5G launch using EP CNo advanced 5G features#4NSA5GCNRNR anchor + 5GC benefits Complex integration#5SA5GCLTEEarly 5GC adoption with LTE Limited to LTE speeds#7NSA5GCLTE + NR Dual connectivity with 5GCComplex deployment
- Migration Strategies for Operators
Operators choose their approach based on spectrum availability, investment plans, and their target markets.
Early 5G Rollouts: Generally, they start with Option #3 (NSA LTE + NR under EPC) for a quick launch.
Mid-Term Migration: Move on to Option #7 (NSA LTE + NR under 5GC) or Option #5 (SA LTE under 5GC).
Long-Term Vision: Fully transition eventually to Option #2 (SA NR under 5GC).
This phased evolution helps operators find the right balance between CAPEX efficiency and service innovation.
Why These Options Matter
The choice of deployment path really influences:
Network Performance: NSA modes might boost speeds but won’t achieve ultra-low latency.
Service Innovation: Only SA NR + 5GC can handle advanced 5G use cases, like autonomous driving or industrial IoT.
Investment Roadmap: Operators can spread out costs gradually rather than having to replace everything at once.
Real-World Deployment Examples
Option #3 (NSA LTE + NR under EPC): Most global operators, including Verizon and Vodafone, kicked off their 5G journeys with this option.
Option #7 (NSA LTE + NR under 5GC): Starting to appear in markets with robust LTE coverage and initial 5GC adoption.
Option #2 (SA NR under 5GC): Countries like China and South Korea are making strides here, where NR spectrum and 5GC deployments are well underway.
Option #5 (SA LTE under 5GC): Considering this in rural areas where NR spectrum is still a challenge.
Conclusion
The 5G deployment options (SA and NSA, EPC vs 5GC) give telecom operators a flexible roadmap for advancement.
Option #3 enabled speedy launches via EPC.
Options #7 and #5 facilitate 5GC integration with either dual connectivity or LTE.
Ultimately, Option #2 stands as the goal — purely NR with 5GC for harnessing full 5G potential.