Kids IT Lab No.17 | Network

What Is 5G?

You've probably seen "5G" in the top corner of your phone's screen. It's the latest generation of mobile communications, launched commercially in Japan in 2020. Beyond being "fast," 5G has two other major strengths: ultra-low latency and the ability to connect a massive number of devices at once. This article explains what makes 5G different from 4G and what really changed.

What Is 5G?

5G stands for "5th Generation." It's the newest version of mobile communication standards — a lineage that started with 1G (voice calls) in 1979. The specifications are set by an international body called 3GPP. In Japan, Docomo, au, SoftBank, and Rakuten Mobile launched commercial 5G service in 2020.

5G isn't just about smartphones. Because the communication foundation itself changes, it becomes much easier to connect factory machines, hospital equipment, cars, cameras, and sensors to the network. That said, even if your phone supports 5G, it falls back to 4G outside 5G coverage areas.

4G vs. 5G

4G vs. 5G: 3-Axis Comparison (theoretical values) Big improvements in speed, latency, and simultaneous connections. Real-world speeds vary by area and signal. 4G (LTE) 5G ① Peak speed Video and large-file downloads Up to 1 Gbps Up to 10–20 Gbps (10–20×) ② Latency (response time) Critical for remote control and self-driving 30–50 ms 1 ms (theoretical; 30× faster) ③ Simultaneous connections Critical for IoT and smart cities 100K devices/km² 1 million devices/km² (10×) Commercial launch & coverage 2010 — nationwide 2020 — urban areas first 5G tower rollout is still ongoing. Rural and residential areas may still be 4G-only.
Fig. 1: 5G is 10× faster, 30× lower latency, 10× more connections. Outside coverage, 4G is used.

5G's Three Strengths and Their Uses

Three New Use Cases 5G Opens Up It's not just "faster smartphones." 5G has the potential to reshape entire industries. ① eMBB: High-speed, high-capacity (for people) 4K/8K video, VR/AR streaming, large downloads on a smartphone Examples: multi-angle live concerts, sports-viewing apps with instant replays → The most immediate benefit. Downloads feel noticeably faster inside coverage areas. ② URLLC: Ultra-low latency (for machines) Factory robots, remote surgery, and self-driving cars operating at 1 ms latency Examples: remote operation of heavy machinery; drone control at disaster sites → Enables life-critical remote operations that 4G's 30 ms latency made impossible. ③ mMTC: Massive machine connections (for IoT) Up to 1 million devices per km² connected simultaneously Examples: smart-city sensor networks, agriculture IoT, logistics tracking → A world where traffic signals, streetlights, and vending machines all connect to the internet.
Fig. 2: 5G is designed to serve people, machines, and IoT all at once — reshaping entire industries.

4G was mainly built for people watching video on smartphones. 5G adds "machine-to-machine communication," "latency-sensitive tasks like medicine and self-driving," and "dense sensor networks across entire cities."

That said, 5G's theoretical maximum won't show up on your phone. Real-world speeds depend on which frequency band is in use, your distance from a tower, whether you're indoors or outdoors, and how many users are nearby. Millimeter-wave (mmWave) frequencies are extremely fast but have short range and can't pass through walls easily.

How Teens Can Observe 5G

Check your phone's settings to see if it supports 5G. Look for something like Settings → Mobile Data → Data Options → Voice & Data → 5G On. If that option exists, your phone supports it. As you move around town, watch how your signal icon switches between "5G," "4G," and "LTE" — it's a real-time map of 5G coverage near you.

When observing, don't rely on the icon alone — actually measure speeds. Switch between 4G and 5G at the same spot and compare download speed, upload speed, and ping. Some spots show 5G but are nearly identical to 4G; others — near stations or shopping centers — can be dramatically faster.

Common Pitfalls

5G myths and real watch-outs
  • "5G = always faster" is not true. Depending on the band (Sub-6 vs. mmWave) and tower distance, measured speeds can sometimes be slower than 4G.
  • 5G uses slightly more battery than 4G. If 4G is fast enough for your daily use, there's no reason to force 5G all the time.
  • Claims that "5G radiation is harmful" are misinformation. The World Health Organization (WHO) and major scientific bodies have found no credible evidence of health harm from 5G signals.

How This Helps Your Future

5G's ultra-low latency will expand new services — self-driving cars, telemedicine, remote machinery operation, XR streaming. No matter which industry you enter — telecom, automotive, medical devices, robotics, or gaming — understanding how 5G works will be considered foundational knowledge.

Learning about 5G also teaches you that "communication isn't only about speed." Latency, simultaneous connections, coverage design, base station placement, signal propagation — these concepts matter not just in telecom careers, but in any job related to IoT or smart cities.

Try It Today

3 steps to get started
  1. Check your phone's settings to confirm whether 5G is turned on.
  2. Use fast.com to measure and compare speeds on 4G vs. 5G at the same location.
  3. Open your carrier's official coverage map and check whether your home, school, and commute route are in 5G coverage.

Summary

5G improves mobile communication across three dimensions: speed, latency, and simultaneous connections. It matters not only for streaming video on smartphones but also for machines, remote operations, and smart cities. Right now we're in a mixed 4G/5G phase — as more towers go up, the range of what's possible keeps growing.

Check 5G changes which numbers?

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