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Question
What are the four types of wireless networks, and how do they differ in range and standards?
Answer
The four types are: WPAN (personal, Bluetooth, ~10m), WLAN (local, Wi-Fi 802.11, ~100m), WMAN (metro, WiMAX 802.16, ~50km), and WWAN (wide, cellular 4G/5G, nationwide).
| Type | Standard | Range | Frequency | Example |
|---|---|---|---|---|
| WPAN | IEEE 802.15 | 6-9 meters (20-30 ft) | 2.4 GHz | Bluetooth, Zigbee |
| WLAN | IEEE 802.11 | Up to ~100m indoor | 2.4 / 5 / 6 GHz | Wi-Fi (home, office, campus) |
| WMAN | IEEE 802.16 | Up to 50 km | Licensed bands | WiMAX (metro broadband) |
| WWAN | Cellular | National/global | Licensed bands | 4G LTE, 5G (mobile data) |
Bluetooth variants:
- Bluetooth BR/EDR (Basic Rate/Enhanced Data Rate): Point-to-point, optimized for audio streaming
- Bluetooth Low Energy (BLE): Supports mesh topology, designed for IoT sensors with minimal power
Other wireless technologies:
- Cellular broadband: GSM (international standard) and CDMA (primarily US)
- Satellite broadband: Requires directional dish, geostationary orbit, used in rural areas where cable/DSL unavailable
Go deeper:
Wireless network (Wikipedia) — the WPAN/WLAN/WMAN/WWAN categories with ranges and IEEE 802.11/802.15/802.16 standards.
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Question
What are the main 802.11 WLAN standards, and what frequency band, speed, and features does each offer?
Answer
The standards evolved from 802.11b (2.4 GHz, 11 Mbps) through 802.11n/ac (MIMO, gigabit speeds) to 802.11ax (Wi-Fi 6, OFDMA, multi-band). Each generation dramatically increased throughput.
| Standard | Wi-Fi Name | Frequency | Max Speed | Key Innovation |
|---|---|---|---|---|
| 802.11 | — | 2.4 GHz | 2 Mbps | Original standard |
| 802.11a | — | 5 GHz | 54 Mbps | Higher frequency, shorter range, not compatible with b/g |
| 802.11b | — | 2.4 GHz | 11 Mbps | First widely adopted, good wall penetration |
| 802.11g | — | 2.4 GHz | 54 Mbps | Backward compatible with 802.11b |
| 802.11n | Wi-Fi 4 | 2.4 + 5 GHz | 600 Mbps | MIMO — multiple antennas for parallel data streams |
| 802.11ac | Wi-Fi 5 | 5 GHz | 1.3+ Gbps | MU-MIMO, up to 8 antennas, wider channels |
| 802.11ax | Wi-Fi 6/6E | 2.4 + 5 + 6 GHz | 9.6 Gbps | OFDMA, HEW (High-Efficiency Wireless), supports 1-7 GHz |
2.4 GHz vs 5 GHz trade-offs:
- 2.4 GHz: Better range and wall penetration, but only 3 non-overlapping channels (1, 6, 11) and crowded spectrum (microwaves, Bluetooth interfere)
- 5 GHz: More channels (24+), less interference, higher throughput, but shorter range and worse wall penetration
Go deeper:
- IEEE 802.11 (Wikipedia) — comparison table of a/b/g/n/ac/ax bands, speeds, and MIMO/OFDMA features.
Rbeede, Liebeskind (original) · CC BY 3.0 · Wikimedia Commons
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