What 5G actually is, how the radio (NR) and the 5G Core fit together, NSA vs SA, the spectrum, the use cases, and every key procedure — grounded in real 3GPP specifications. The deepest hands-on 5G resource on the web, built by working RF and core engineers.
5G is the fifth generation of mobile networks — standardised by the ITU as IMT-2020 and by 3GPP as New Radio (NR) plus the 5G Core (5GC), starting in Release 15 (2018). It is built around three usage families: eMBB (fast broadband), URLLC (ultra-reliable low-latency) and mMTC (massive IoT).
5G has two halves that work together: the radio — 5G NR, defined in the 3GPP 38-series (TS 38.211–214 for the physical layer, TS 38.300/331 for the RAN) — and the core — the 5G Core, a cloud-native service-based architecture defined in TS 23.501/502/503. Together they replace 4G's E-UTRAN radio and EPC core.
New here? Start with the 5G Core deep-dive and the 5G NR glossary, then see where it's all heading next in the 6G hub.
| Dimension | 4G LTE (IMT-Advanced) | 5G (IMT-2020) |
|---|---|---|
| Standard | 3GPP Rel-8+ · IMT-Advanced | 3GPP Rel-15+ · IMT-2020 |
| Peak downlink | ~1 Gbit/s | 20 Gbit/s |
| Over-the-air latency | ~10 ms | 1 ms (URLLC) |
| Spectrum | sub-6 GHz | FR1 sub-7 GHz + FR2 mmWave 24–71 GHz |
| Core network | EPC (point-to-point) | 5G Core (Service-Based Architecture) |
| Radio waveform / coding | OFDMA, fixed 15 kHz SCS, Turbo | CP-OFDM, flexible numerology, LDPC + Polar |
| RRC states | IDLE / CONNECTED | + RRC_INACTIVE |
| Use cases | Mobile broadband | eMBB + URLLC + mMTC |
| MIMO | up to 8 layers | massive MIMO (up to 256 elements), beamforming |
| Connection density | 10⁵ /km² | 10⁶ /km² |
Security angle: 5G Security vs 4G Security — a 3GPP analysis. PHY angle: 5G NR vs LTE physical layer.
5G splits cleanly into a radio access network (NG-RAN, made of gNBs) and the 5G Core. The 5GC is service-based: its network functions expose REST/HTTP-2 service APIs instead of rigid point-to-point links, with control- and user-plane separation.
AMF (access & mobility), SMF (session management), UPF (user-plane forwarding), PCF (policy), UDM/UDR (subscriber data), AUSF (authentication), NRF (NF discovery), NSSF (slice selection), NEF (exposure) and NWDAF (analytics). Defined in TS 23.501.
NSA (Non-Standalone, Option 3 / EN-DC) anchors NR to a 4G LTE cell and the EPC — quick to launch. SA (Standalone, Option 2) runs NR on the 5G Core, unlocking slicing, URLLC and the full SBA. Learn the migration path in the 5G NSA masterclass.
Go deeper: 5G Core Architecture (with 3GPP specs) · 5G Core & security architecture · build it live in the 5G Core lab.
NR's physical layer is where 5G's flexibility lives: scalable numerology (subcarrier spacing 15–240 kHz), bandwidth parts, CP-OFDM with optional DFT-s-OFDM on the uplink, LDPC for data and Polar for control, and beam-based synchronisation via the SS/PBCH block.
μ = 0–4, 15–240 kHz.
LEARN →Frames, slots, the resource grid.
LEARN →PSS/SSS/PBCH, beam sweep.
LEARN →Cell search to RACH.
LEARN →Preambles & formats.
LEARN →4-step & 2-step.
LEARN →Downlink shared channel.
LEARN →Demodulation reference signals.
LEARN →NR channel coding.
LEARN →BWP configuration.
LEARN →Hybrid ARQ in NR.
LEARN →Quasi-co-location, beams.
LEARN →The full course: 5G NR Physical Layer · Advanced (99 lessons, TS 38.211–215) · the book: 5G NR PHY Handbook.
| Range | Frequencies | Role |
|---|---|---|
| FR1 (sub-6 / sub-7) | 410 MHz – 7.125 GHz | Coverage + capacity — the workhorse 5G bands (e.g. n78 3.5 GHz, n28 700 MHz, C-band). |
| FR2-1 (mmWave) | 24.25 – 52.6 GHz | Very high capacity, short range — dense urban, venues, fixed wireless. |
| FR2-2 (mmWave) | 52.6 – 71 GHz | Extended mmWave added in Rel-17. |
Regional reality checks: 5G in the USA (C-band, mmWave, FWA) · 5G in the Middle East & GCC · 5G & Open RAN in Europe.
5G's three usage families map onto the famous ITU triangle. Network slicing is what makes serving all three on one network practical.
Enhanced mobile broadband — multi-Gbps video, XR, FWA.
Ultra-reliable low-latency — industrial control, V2X, remote ops.
Massive machine-type — huge fleets of low-power IoT sensors.
One network, many isolated logical networks (S-NSSAI).
Hands-on: the network slicing lab · voice on 5G: VoLTE & VoNR call-flow deep-dive · private 5G: 5G private network course.
NR (NSA then SA), the 5G Core, eMBB.
URLLC enhancements, NR-U (unlicensed), V2X sidelink, positioning, IAB.
RedCap, NTN, FR2-2 (52.6–71 GHz), coverage & power enhancements.
AI/ML for the air interface, network energy saving, XR, MIMO evolution.
Deep-dive articles, hands-on browser labs, structured courses and books — all built by working engineers, grounded in 3GPP.
53 lessons · architecture → L1–L3.
VIEW →Every NF, interface & procedure.
VIEW →99 lessons · TS 38.211–215.
VIEW →EN-DC, NSA → SA migration.
VIEW →The physical-layer book.
READ →18 chapters · 33 modules.
READ →KPIs · drive test · counters.
READ →The disaggregated 5G RAN hub.
EXPLORE →Browser labs on a live 5G core, cinematic courses, and deep-dive books — built by field engineers, grounded in 3GPP. Lifetime access from $16.49.