Level 1
4G LTE Essentials
You cannot understand 5G without understanding what it evolved from. Master LTE architecture, air interface, key procedures, VoLTE, and see how every 4G concept maps directly to 5G.
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LTE Architecture Overview
0/7Explore the end-to-end LTE/EPC architecture — from the radio access network (E-UTRAN) through every core network function.
LTE end-to-end architecture at a glance
See the complete LTE system — UE, eNodeB, MME, SGW, PGW, HSS, PCRF — and understand how they connect.
lesson3 min
E-UTRAN: eNodeB and the radio side
Understand the eNodeB — LTE's base station — its components, X2 interface, and role in the radio access network.
lesson3 min
EPC: MME, SGW, PGW — what each does
Follow data through the Evolved Packet Core and see the role of each network element in real time.
animation3 min
HSS and subscriber data management
Learn how the Home Subscriber Server stores subscriber profiles, authentication keys, and location information.
lesson2 min
PCRF and policy control in LTE
Understand how the PCRF enforces QoS policies, charging rules, and bandwidth limits for each subscriber.
lesson2 min
Lab: Build the LTE architecture
Drag-and-drop eNB, MME, SGW, PGW, HSS onto the canvas and connect them with S1, S5, S6a, S11 interfaces.
topology5 min
Quiz: LTE architecture
Test your knowledge of LTE architecture, EPC components, and their interconnections.
quiz3 min
LTE Air Interface Basics
0/5Dive into OFDMA, resource blocks, LTE channels, and bandwidth options — the foundation of LTE radio communication.
OFDMA and SC-FDMA — LTE's radio technology
Visualize how OFDMA splits the spectrum into thousands of narrow subcarriers for efficient parallel data transmission.
animation3 min
Resource blocks, slots, and frames
Explore the LTE resource grid — 12 subcarriers × 7 symbols = 1 resource block — and how the scheduler allocates them.
lesson3 min
LTE channels: logical, transport, physical
Understand the three-tier channel architecture and how data flows from logical to transport to physical channels.
animation3 min
LTE bandwidth options (1.4 to 20 MHz)
Compare all 6 LTE bandwidth configurations and see how each affects capacity, resource blocks, and throughput.
lesson2 min
Quiz: LTE air interface
Test your understanding of OFDMA, resource blocks, channels, and LTE bandwidth options.
quiz3 min
LTE Key Procedures
0/8Master the essential LTE signaling procedures — attach, bearer setup, handover, detach, and TAU — through animated call flows.
LTE Attach procedure
Watch the complete LTE attach call flow: UE → eNB → MME → HSS → SGW → PGW, step by step.
animation4 min
LTE Default bearer establishment
See how a default EPS bearer is established during attach, creating the data path for the UE.
animation3 min
LTE Handover (X2 and S1)
Compare X2-based (direct eNB-to-eNB) and S1-based (via MME) handover procedures side by side.
animation4 min
LTE Detach procedure
Follow the UE-initiated and network-initiated detach procedures and understand resource cleanup.
animation3 min
Tracking Area Update (TAU)
See how the UE updates its location when moving between tracking areas without active data transfer.
animation3 min
Real-world: What happens when your LTE call drops
Analyze the top 5 causes of LTE call drops and learn to identify root causes from network symptoms.
lesson3 min
Lab: Trace an LTE attach using log analysis
Read a simulated protocol log, identify each attach step, and pinpoint where failures occur.
lab5 min
Quiz: LTE procedures
Scenario-based questions on attach, handover, detach, and troubleshooting LTE procedures.
quiz3 min
VoLTE Basics
0/7Learn how voice works over LTE — IMS architecture, VoLTE call flows, dedicated bearers, and SRVCC fallback.
Why voice over LTE needs IMS
Understand why LTE — a pure IP network — needs the IP Multimedia Subsystem to deliver voice services.
lesson3 min
IMS components: P-CSCF, S-CSCF, I-CSCF
Explore the three Call Session Control Functions and how they work together to manage VoLTE calls.
lesson3 min
VoLTE call flow (MO to MT)
Watch the full Mobile Originating to Mobile Terminating VoLTE call flow through IMS and EPC.
animation4 min
Dedicated bearer for voice (QCI 1)
See how a dedicated bearer with QCI 1 is created for voice — guaranteed low latency and priority.
animation3 min
SRVCC: fallback to 3G/2G during a call
Understand Single Radio Voice Call Continuity — how a VoLTE call seamlessly falls back to 3G circuit-switched.
animation3 min
Real-world: Why VoLTE calls sound better than 3G
Compare AMR-NB (3G) vs AMR-WB/EVS (VoLTE) codecs and understand the HD voice experience.
lesson2 min
Quiz: VoLTE
Test your knowledge of IMS architecture, VoLTE procedures, bearers, and SRVCC.
quiz3 min
4G vs 5G Comparison
0/6Bridge LTE and 5G — map every EPC component to its 5G equivalent and understand the key architectural shifts.
Architecture comparison: EPC vs 5GC
See the LTE EPC and 5G Core side by side — monolithic vs service-based architecture.
lesson3 min
NF mapping: MME → AMF+SMF, SGW/PGW → UPF
Watch how each LTE network function maps to one or more 5G equivalents with animated transitions.
animation3 min
Interface comparison: S1/X2 vs NG/Xn
Compare LTE interfaces (S1-MME, S1-U, X2, S5, S11) with their 5G counterparts (N1-N11, NG, Xn).
lesson2 min
Key improvements: speed, latency, capacity, slicing
Visualize the quantum leap from 4G to 5G in throughput, latency, device density, and network slicing.
animation3 min
Lab: Map every LTE component to its 5G equivalent
Drag-and-drop matching: connect each LTE element (eNB, MME, SGW, PGW, HSS, PCRF) to its 5G counterpart.
lab5 min
Quiz: 4G vs 5G (Level Gate)
10 questions covering the full Level 1 — pass this to unlock Level 2: 5G Fundamentals.
quiz5 min