5G - 5th Generation Mobile Network
5G is the 5th generation mobile network technology, consisting of 5G Core (5GC) for the core network and NR (New Radio) for the radio access. It was standardized starting with Rel-15 (2018), enhanced in Rel-16 (2020), and extended in Rel-17 (2022).
Key Features
5G introduces revolutionary capabilities:
- 5G Core (5GC) - service-based cloud-native core network
- NR (New Radio) - new radio interface with gNB base stations
- Higher frequencies - FR1 (sub-6 GHz) + FR2 (mmWave 24-52 GHz)
- Scalable numerology - flexible subcarrier spacing (15-240 kHz)
- Massive MIMO - up to 256 antenna elements
- Network slicing - virtual networks for different services
- Ultra-low latency - <1ms target for URLLC
๐ Specifications: TS 38.300 (NR Overall), TS 23.501 (5GS Architecture)
5G Use Cases
IMT-2020 Triangle
| Use Case |
Description |
Requirements |
| eMBB |
Enhanced Mobile Broadband |
20 Gbps DL, 10 Gbps UL |
| URLLC |
Ultra-Reliable Low Latency |
<1ms, 99.999% reliability |
| mMTC |
Massive Machine Type Comm |
1M devices/kmยฒ |
Application Examples
| Category |
Applications |
| eMBB |
4K/8K video, VR/AR, cloud gaming |
| URLLC |
Industrial automation, remote surgery, autonomous driving |
| mMTC |
Smart cities, agriculture, logistics |
Network Architecture
Deployment Options
Non-Standalone (NSA)
โโโโโโโโโโโโโโโ
โ EPC (4G) โ
โโโโโโโโฌโโโโโโโ
โ
โโโโโดโโโโ
โ eNB โโโโX2โโโโโโโโโโโโ
โ (LTE) โ โ gNB โ
โโโโโฌโโโโ โ (NR) โ
โ โโโโโฌโโโโ
โโโโโโโโโโฌโโโโโโโโ
โ
โโโโดโโโ
โ UE โ
โโโโโโโ
Option 3/3a/3x: LTE anchor + NR for data boost (EN-DC)
Standalone (SA)
โโโโโโโโโโโโโโโ
โ 5GC (5G) โ
โโโโโโโโฌโโโโโโโ
โ N2/N3
โโโโโดโโโโ
โ gNB โ
โ (NR) โ
โโโโโฌโโโโ
โ
โโโโดโโโ
โ UE โ
โโโโโโโ
Option 2: Full 5G with 5G Core
See the detailed glossary entry for evolution across releases.
| Component |
Full Name |
Function |
| AMF |
Access and Mobility Management |
MM, authentication |
| SMF |
Session Management Function |
Session management, IP |
| UPF |
User Plane Function |
Data forwarding, QoS |
| UDM |
Unified Data Management |
Subscriber data |
| PCF |
Policy Control Function |
Policies |
| AUSF |
Authentication Server |
Authentication |
| NSSF |
Network Slice Selection |
Slice selection |
| NRF |
Network Repository Function |
Service discovery |
Interfaces
| Interface |
Connection |
Protocol |
| N1 |
UE โ AMF |
NAS |
| N2 |
gNB โ AMF |
NGAP |
| N3 |
gNB โ UPF |
GTP-U |
| N4 |
SMF โ UPF |
PFCP |
| Xn |
gNB โ gNB |
Xn-AP |
๐ Specifications: TS 23.501 (System Architecture), TS 38.401 (NG-RAN Architecture)
NR Physical Layer
Scalable Numerology
| ฮผ |
SCS (kHz) |
Slot (ms) |
Symbols/slot |
CP |
Use Case |
| 0 |
15 |
1.0 |
14 |
Normal |
Sub-6 GHz |
| 1 |
30 |
0.5 |
14 |
Normal |
Sub-6 GHz |
| 2 |
60 |
0.25 |
14 |
Normal/Ext |
FR1/FR2 |
| 3 |
120 |
0.125 |
14 |
Normal |
mmWave |
| 4 |
240 |
0.0625 |
14 |
Normal |
mmWave sync |
NR vs LTE Comparison
| Feature |
LTE |
NR |
| SCS |
15 kHz fixed |
15-240 kHz |
| Max BW |
20 MHz |
100/400 MHz |
| Slot length |
1 ms |
0.0625-1 ms |
| Mini-slot |
No |
2/4/7 symbols |
| Waveform DL |
OFDM |
OFDM |
| Waveform UL |
SC-FDMA |
OFDM + SC-FDMA |
| Ref signals |
CRS always-on |
DMRS on-demand |
Physical Channels
| Channel |
Direction |
Purpose |
| PBCH |
DL |
Broadcast (MIB) |
| PDCCH |
DL |
Control (DCI) |
| PDSCH |
DL |
Shared data |
| PUCCH |
UL |
Control (UCI) |
| PUSCH |
UL |
Shared data |
| PRACH |
UL |
Random access |
Reference Signals
| Signal |
Purpose |
When |
| DMRS |
Demodulation |
With data |
| CSI-RS |
Channel state |
Periodic/triggered |
| PT-RS |
Phase tracking |
mmWave |
| SRS |
Sounding (UL) |
UL channel estimation |
๐ Specifications: TS 38.211 (Physical Channels), TS 38.212 (Multiplexing)
Frequency Bands
FR1 (Sub-6 GHz)
| Band |
Frequency |
Duplex |
Region |
| n1 |
2100 MHz |
FDD |
Global |
| n3 |
1800 MHz |
FDD |
Global |
| n28 |
700 MHz |
FDD |
APAC/EU |
| n41 |
2.5 GHz |
TDD |
USA/China |
| n77 |
3.3-4.2 GHz |
TDD |
Global (C-band) |
| n78 |
3.3-3.8 GHz |
TDD |
Global (C-band) |
| n79 |
4.4-5.0 GHz |
TDD |
Japan/China |
FR2 (mmWave)
| Band |
Frequency |
Max BW |
Region |
| n257 |
26.5-29.5 GHz |
400 MHz |
Global |
| n258 |
24.25-27.5 GHz |
400 MHz |
Global |
| n260 |
37-40 GHz |
400 MHz |
USA |
| n261 |
27.5-28.35 GHz |
400 MHz |
USA |
Bandwidth
| FR |
Max Channel BW |
Max Aggregated |
| FR1 |
100 MHz |
800 MHz (8 CC) |
| FR2 |
400 MHz |
1.6 GHz (4 CC) |
๐ Specifications: TS 38.101-1 (FR1 RF), TS 38.101-2 (FR2 RF)
Massive MIMO is essential for 5G NR performance. See the detailed glossary entry for evolution across releases.
Massive MIMO in NR
| Configuration |
Antennas |
Typical Use |
| 32T32R |
64 elements |
Urban macro |
| 64T64R |
128 elements |
Dense urban |
| 128T128R |
256 elements |
High capacity |
| Type |
Description |
Use Case |
| Analog |
Single beam, phase shifters |
mmWave |
| Digital |
Multiple beams, baseband |
FR1 |
| Hybrid |
Combined approach |
FR2 |
Beam Management
| Procedure |
Purpose |
| Beam sweeping |
Initial access, find best beam |
| Beam measurement |
UE reports best beam |
| Beam indication |
Network indicates active beam |
| Beam recovery |
Recover from beam failure |
SSB Beams
| FR |
Max SSB Beams |
Period |
| FR1 |
4-8 |
5-160 ms |
| FR2 |
64 |
5-160 ms |
๐ Specifications: TS 38.214 (Physical Layer Procedures)
Network Slicing
Network Slicing enables creating multiple virtual networks on shared infrastructure. See the detailed glossary entry for evolution across releases.
Slice Types (SST)
| SST |
Name |
Use Case |
| 1 |
eMBB |
Broadband |
| 2 |
URLLC |
Low latency |
| 3 |
MIoT |
Massive IoT |
| 4 |
V2X |
Vehicles |
S-NSSAI Components
| Field |
Description |
| SST |
Slice/Service Type (8 bits) |
| SD |
Slice Differentiator (24 bits, optional) |
Slice Architecture
โโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโโ
โ Physical Network โ
โโโโโโโโโโโโโโโฌโโโโโโโโโโโโโโฌโโโโโโโโโโโโโโโโโโค
โ Slice 1 โ Slice 2 โ Slice 3 โ
โ eMBB โ URLLC โ mMTC โ
โ โ โ โ
โ โโโโโโโโโ โ โโโโโโโโโ โ โโโโโโโโโโโโโ โ
โ โ AMF โ โ โ AMF โ โ โ AMF โ โ
โ โ SMF โ โ โ SMF โ โ โ SMF โ โ
โ โ UPF โ โ โ UPF โ โ โ UPF โ โ
โ โโโโโโโโโ โ โโโโโโโโโ โ โโโโโโโโโโโโโ โ
โโโโโโโโโโโโโโโดโโโโโโโโโโโโโโดโโโโโโโโโโโโโโโโโโ
๐ Specifications: TS 23.501 ยง5.15 (Network Slicing), TS 28.531 (Slice Management)
URLLC
Ultra-Reliable Low-Latency Communications (URLLC) - mission-critical services. See the detailed glossary entry for evolution across releases.
Requirements
| Parameter |
URLLC Target |
| User plane latency |
<1 ms |
| Reliability |
99.999% (5 nines) |
| Jitter |
<1 ms |
| Availability |
99.9999% |
URLLC Features (Rel-15/16)
| Feature |
Description |
| Mini-slot |
2/4/7 symbol transmission |
| Grant-free UL |
Configured grant (no SR delay) |
| Preemption |
URLLC preempts eMBB |
| PDCP duplication |
Same packet on multiple paths |
| Multi-TRP |
Transmit from multiple points |
Latency Breakdown
| Component |
Target |
| Processing (UE TX) |
0.2 ms |
| Frame alignment |
0.1 ms |
| TTI |
0.125 ms (ฮผ=3) |
| Processing (gNB) |
0.2 ms |
| Total one-way |
<0.5 ms |
๐ Specifications: TS 38.300 ยง8.3 (URLLC), TR 38.824 (URLLC Study)
NR-V2X
NR-based Vehicle-to-Everything - Rel-16 evolution of LTE V2X.
NR-V2X vs LTE-V2X
| Feature |
LTE-V2X (Rel-14/15) |
NR-V2X (Rel-16) |
| Latency |
20-100 ms |
3-10 ms |
| Reliability |
90% |
99.99% |
| Data rate |
10s of Mbps |
100s of Mbps |
| Range |
400 m |
1000 m (LOS) |
| Unicast |
No |
Yes |
| Groupcast |
No |
Yes |
NR Sidelink
| Feature |
Description |
| Unicast |
Point-to-point |
| Groupcast |
One-to-many |
| Broadcast |
One-to-all |
| HARQ feedback |
Unicast/groupcast |
Resource Allocation
| Mode |
Description |
| Mode 1 |
Network scheduled |
| Mode 2 |
UE autonomous (sensing) |
๐ Specifications: TS 38.300 ยง16 (Sidelink), TS 23.287 (5G V2X)
Rel-17 Features
RedCap (Reduced Capability)
| Feature |
NR RedCap |
vs Full NR |
| Max BW |
20 MHz FR1, 100 MHz FR2 |
100/400 MHz |
| Antennas |
1ร1 or 1ร2 |
2ร2 or 4ร4 |
| Duplex |
HD-FDD option |
FDD/TDD |
| Target devices |
Wearables, sensors, cameras |
Smartphones |
NTN (Non-Terrestrial Networks)
| Platform |
Altitude |
Latency |
| LEO |
300-1500 km |
5-25 ms |
| MEO |
7000-25000 km |
50-150 ms |
| GEO |
35786 km |
270-300 ms |
| HAPS |
20 km |
<1 ms |
NTN Adaptations:
- Extended HARQ timing
- GNSS-based timing
- Doppler pre-compensation
- Extended TA
Other Rel-17 Features
| Feature |
Description |
| NR positioning |
cm-level accuracy |
| Multi-SIM |
MUSIM support |
| DSS enhancements |
Better LTE/NR sharing |
| 52.6-71 GHz |
Extended FR2 |
| Sidelink relay |
UE-to-Network relay |
๐ Specifications: TS 38.300 (NR Overall), TR 38.811 (NTN Study)
UE Categories
NR doesn't use traditional UE categories like LTE. Instead, capability is defined by:
Capability Parameters
| Parameter |
Range |
| Max layers DL |
1-8 |
| Max layers UL |
1-4 |
| Max modulation |
256QAM/1024QAM |
| Max bandwidth |
100/200/400 MHz |
| CA support |
Band combinations |
Device Classes
| Class |
Peak DL |
Use Case |
| High-end smartphone |
>2 Gbps |
eMBB |
| Mid-range |
~1 Gbps |
General |
| RedCap |
~150 Mbps |
Wearables/IoT |
| Industrial |
Variable |
URLLC focus |
๐ Specifications: TS 38.306 (UE Radio Access Capabilities)
Timeline
- 2015 - 5G NR study started
- 2017 - NSA NR specification (Rel-15 early drop)
- 2018 - Rel-15 frozen (full NSA + SA)
- 2019 - First commercial 5G networks (Korea, USA)
- 2020 - Rel-16 frozen (URLLC, V2X, IAB)
- 2021 - 5G SA deployments expand
- 2022 - Rel-17 frozen (RedCap, NTN)