Why Is It Difficult to Understand 1G, 2G, 3G, 4G, 5G, and the Future 6G
Networks?

How Did They Evolve Historically, What Changed Technologically, and How Can
They Be Simulated in ns-3?

1. Why Do 1G–6G Cellular Networks Cause So Much Conceptual Confusion?

The confusion mainly arises because three distinct domains are often mixed
together:

1. Radio signal theory (waves, modulation, spectrum)
2. Network engineering (packets, protocols, routing)
3. Simulation abstraction (models, not physical reality)

Cellular generations are defined mostly by radio access and core-network
architecture, whereas ns-3 operates at the packet and protocol level.
Once this separation is understood, the apparent complexity becomes manageable.

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2. What Does the Term “Generation (G)” Actually Represent?

A new “G” does not simply mean higher data rates.
It marks a fundamental
architectural shift in one or more of the following:

Thus, each generation reflects a new network philosophy, not just faster
radios.

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3. What Was 1G and Why Can’t It Be Simulated in ns-3?

📜 Historical perspective

1G systems (1980s) such as AMPS and NMT were designed purely for analog voice
communication.

📡 Technological characteristics

• Analog FM
• FDMA
• Circuit-switched
• No data, no encryption

🧪 Simulation perspective

ns-3 cannot simulate 1G, because:

• It is analog and continuous
• No packet-based communication exists
• No protocol stack is present

👉 1G belongs to communication theory, not network simulation.

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4. How Did 2G Improve Upon 1G, and Why Is It Still Hard to Simulate?

📜 Historical perspective

2G (1990s) introduced digital cellular communication, with GSM becoming
dominant worldwide.

📡 Technological characteristics

Enhancements:

• GPRS (2.5G): packet data
• EDGE (2.75G): higher throughput

🧪 Simulation perspective

ns-3 does not implement GSM PHY/MAC.
Researchers usually model:

• Traffic flows
• Delays and losses
• Abstract access links

👉 2G is conceptually modeled, not realistically simulated.

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5. What Did 3G Change, and Why Is Its Simulation Rare in ns-3?

📜 Historical perspective

3G (UMTS/WCDMA) enabled mobile internet access for the first time.

📡 Technological characteristics

Key idea:

All users transmit simultaneously, separated by spreading codes.

🧪 Simulation perspective

• CDMA requires chip-level signal modeling
• ns-3 avoids waveform simulation

👉 Full 3G simulation is rare; it is often approximated or skipped.

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6. Why Is 4G (LTE) the Turning Point for ns-3 Simulation?

📜 Historical perspective

4G LTE (2010 onward) made the internet truly mobile.

📡 Technological breakthroughs

Key abstraction:

Time–frequency resource blocks dynamically allocated by schedulers.

🧪 Simulation perspective

✅ Full LTE support exists in ns-3

Simulated components include:

• Abstract PHY (SINR-based)
• MAC schedulers
• RLC / PDCP
• EPC core network
• Mobility and handover
• QoS and energy models

👉 This is why LTE is the baseline cellular model in ns-3 research.

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7. What Makes 5G Different from 4G, and How Well Can ns-3 Model It?

📜 Historical perspective

5G targets humans and machines, not just smartphones.

📡 Technological advancements

Three use cases:

• eMBB
• URLLC
• mMTC

🧪 Simulation perspective

⚠️ Partial support in ns-3

• 5G NR module (LTE-like abstraction)
• mmWave module (beamforming, blockage)

Researchers can study:

• Latency
• Scheduling
• Mobility and handover
• Directional communication

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8. What Is 6G Expected to Be, and Can It Be Simulated Today?

📜 Vision and motivation

6G aims to integrate communication, sensing, intelligence, and space
networks.

📡 Expected technological directions

🧪 Simulation perspective

❌ No standardized 6G modules exist.

However, ns-3 can still be used to:

• Prototype architectural ideas
• Implement AI-driven schedulers
• Study non-terrestrial and deep-space links
• Analyze energy and scalability

👉 6G simulation today is custom, exploratory research, not standards-based.

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9. What Exactly Does ns-3 Simulate—and What Does It Ignore?

What ns-3 simulates well

• Packet flow
• Delay, throughput, loss
• Scheduling and queuing
• Mobility
• Energy consumption

What ns-3 does not simulate

• I/Q samples
• Waveforms
• Antenna radiation
• Hardware impairments

👉 ns-3 is a network-level simulator, not a signal-level one.

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10. How Do Cellular Generations Map to ns-3 Support?

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11. What Is the Simplest Mental Model to Remember All Generations?

1G–3G → How do we make voice mobile?
4G → How do we make the Internet
mobile?
5G → How do we guarantee performance?
6G → How do we make
networks intelligent?

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12. What Is the Key Takeaway for Teaching and Research?

• Do not present generations as speed upgrades
• Emphasize architectural shifts
• Use LTE as the anchor model in ns-3
• Extend toward 5G and future 6G concepts
• Always explain simulation abstraction limits

This approach removes confusion and builds correct intuition for students and
researchers.

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Comparison Chart: 1G → 6G and ns-3 Simulation Perspective

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Quick Interpretation Guide

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One-Line Memory Hook

1G–3G: Making voice mobile
4G: Making the Internet mobile
5G: Making
performance predictable
6G: Making networks intelligent

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