Wireless Network Technologies - Lesson 2.2

Wi-Fi Standards and IEEE 802.11

The IEEE (Institute of Electrical and Electronics Engineers) standardizes wireless networks through the 802.11 committee, commonly referred to as 802.11 networks or Wi-Fi.
To simplify naming, the IEEE adopted consumer-friendly names:
- 802.11ac → Wi-Fi 5
- 802.11ax → Wi-Fi 6 (and Wi-Fi 6E for extended support)
- 802.11be → Wi-Fi 7
These standards define how devices communicate wirelessly over specific frequencies and channels.

Wi-Fi networks operate on three primary frequency ranges:
- 2.4 GHz – Common but prone to interference due to limited channels.
- 5 GHz – Offers more channels and higher bandwidth options.
- 6 GHz – Introduced with Wi-Fi 6E, providing even more spectrum and less congestion.
Instead of referencing exact frequencies (e.g., 2.437 GHz), Wi-Fi uses channels for easier configuration:
- Example: Channel 6 in 2.4 GHz corresponds to 2.437 GHz.
- Example: Channel 44 in 5 GHz corresponds to 5.220 GHz.
Bandwidth determines the amount of spectrum used for communication:
- Common bandwidths: 20 MHz, 40 MHz, 80 MHz, and 160 MHz.
- Higher bandwidth allows for greater data throughput but may reduce available channels.

2.4 GHz Band:
- Limited non-overlapping channels (typically 3 channels in 20 MHz mode).
- Prone to interference from other devices (e.g., microwaves, Bluetooth).
5 GHz Band:
- More available channels and supports wider bandwidths (40 MHz, 80 MHz, 160 MHz).
- Less interference but shorter range compared to 2.4 GHz.
6 GHz Band (Wi-Fi 6E and later):
- Provides the most spectrum, reducing congestion in high-density areas.
- Supports ultra-high bandwidth for low-latency applications.

Bluetooth:
- Operates in the 2.4 GHz ISM (Industrial, Scientific, and Medical) band.
- Used for short-range connections (e.g., headsets, speakers, keyboards).
- Typical range: 10 meters (33 feet) for consumer devices.
RFID (Radio Frequency Identification):
- Used for identification and tracking (e.g., access badges, pet microchips, inventory tags).
- Two main types:
  - Passive RFID: No battery; powered by the scanner’s radio waves.
  - Active RFID: Battery-powered for longer-range scanning.
- Tags contain an antenna and a chip storing identification data.
NFC (Near Field Communication):
- Extends RFID with two-way communication for interactive applications.
- Common uses:
  - Mobile payments (e.g., smartphones, smartwatches).
  - Device pairing (e.g., Bluetooth/Wi-Fi setup).
  - Access control (e.g., door entry, identification).
- Operates at very short range (~4 cm).