Wi-Fi
Wi-Fi (Wireless Fidelity) allows devices to connect to a network using radio waves instead of physical cables. It is based on the IEEE 802.11 family of standards.
- Operates on 2.4 GHz or 5 GHz frequency bands
- 2.4 GHz: longer range, but slower and more interference; 5 GHz: shorter range, but faster and less interference
- Requires a Wireless Access Point (WAP) to connect devices to the wired network
Advantages of Wi-Fi
- No cables required — flexible and portable
- Easily connect multiple devices
- Convenient for mobile devices
Disadvantages of Wi-Fi
- Generally slower and less reliable than wired connections
- Security risks — signals can be intercepted; needs encryption (WPA2/WPA3)
- Subject to interference from other devices
- Signal weakens with distance and physical obstacles (walls)
Wireless Access Point (WAP)
A Wireless Access Point (WAP) is a device that creates a wireless network by broadcasting a Wi-Fi signal. It connects to the wired network via a cable and allows wireless devices to join the network.
- Can extend a wired network's coverage area
- Multiple WAPs can be placed around a large building to provide complete coverage
Bluetooth
Bluetooth is a short-range wireless technology (typically up to ~10 metres) used for direct device-to-device communication without needing an internet connection or WAP.
- Operates on the 2.4 GHz band
- Low power consumption
- Common uses: headphones, keyboards, mice, smartwatches, file transfer between phones
- Not suitable for long-range or high-bandwidth uses
Mobile Networks (Cellular)
Mobile networks use cell towers to provide wireless internet access over wide areas. Generations of mobile networks:
| Generation | Key features | Approximate speeds |
|---|
| 3G | First to provide mobile internet access; enables video calling | ~2–14 Mbps |
| 4G (LTE) | High-speed mobile internet; supports HD video streaming | ~50–150 Mbps |
| 5G | Very high speed, very low latency; supports IoT and smart cities | ~1–10 Gbps |
Wi-Fi vs Bluetooth vs Mobile
| Feature | Wi-Fi | Bluetooth | Mobile (4G/5G) |
|---|
| Range | ~50–100 m indoors | ~10 m | Several km |
| Speed | High | Low | Medium–High |
| Requires infrastructure | WAP/router | No | Cell towers |
| Common use | Home/office internet | Personal devices | Mobile internet |
Exam tip: Know the key characteristics: Wi-Fi = medium range, requires WAP; Bluetooth = short range (~10m), no infrastructure needed; 4G/5G = wide area coverage via cell towers. Cambridge may ask you to suggest the most appropriate wireless technology for a given scenario — justify your choice with range and context.
⚠️ Common Mistakes
- Confusing WAP with a router — a WAP only handles wireless connections; a router routes between networks
- Saying Bluetooth has the same range as Wi-Fi — Bluetooth is much shorter range (~10m)
- Forgetting that Wi-Fi can be intercepted — always mention that it needs encryption (WPA2/WPA3) as a security measure