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Wireless Networks Overview

Jul 10, 2024

Wireless Networks Overview

Wireless networks are prevalent in homes and businesses, often expected in public places like restaurants and conference rooms.

IEEE 802.11 Standards

The standards for wireless networks come from the IEEE LAN/MAN Standards Committee, specifically the IEEE 802.11 standard. Abbreviated as Wi-Fi, named and tested for interoperability by the Wi-Fi Alliance.

Early Standards

  1. 802.11a

    • Released: October 1999
    • Frequency: 5 GHz
    • Speed: 54 Mbps
    • Range: Shorter than 2.4 GHz due to signal absorption
    • Usage: Rarely in use today

  2. 802.11b

    • Released: October 1999
    • Frequency: 2.4 GHz
    • Speed: 11 Mbps
    • Range: Longer range due to less signal absorption
    • Interference: Common with other devices like baby monitors, cordless phones, and Bluetooth
    • Usage: Rare today, often seen in legacy systems

Upgraded Standards

  1. 802.11g

    • Released: June 2003
    • Frequency: 2.4 GHz
    • Speed: 54 Mbps
    • Compatibility: Backwards compatible with 802.11b
    • Interference: Same as 802.11b

  2. 802.11n (Wi-Fi 4)

    • Released: 2009
    • Frequency: 2.4 GHz and 5 GHz
    • Speed: Up to 600 Mbps (with 4 antennas)
    • Features: MIMO (Multiple Input Multiple Output)
    • Improvement: More bandwidth (40 MHz channels)

  3. 802.11ac (Wi-Fi 5)

    • Released: January 2014
    • Frequency: 5 GHz
    • Speed: Up to 6.9 Gbps
    • Features: Multi-user MIMO, better modulation and channel bandwidths (up to 160 MHz)

  4. 802.11ax (Wi-Fi 6)

    • Released: February 2021
    • Frequency: 2.4 GHz and 5 GHz, can use both simultaneously
    • Speed: Up to 9.6 Gbps (theoretical maximum)
    • Features: OFDMA (Orthogonal Frequency Division Multiple Access) for dense environments, improved efficiency

Summary of Standards

  • 802.11a: 5 GHz, 54 Mbps, no MIMO
  • 802.11b: 2.4 GHz, 11 Mbps, no MIMO
  • 802.11g: 2.4 GHz, 54 Mbps, no MIMO
  • 802.11n: 2.4/5 GHz, up to 600 Mbps, 4-stream MIMO
  • 802.11ac: 5 GHz, up to 6.9 Gbps, 8-stream multi-user MIMO
  • 802.11ax: 2.4/5 GHz, up to 9.6 Gbps, 8-stream multi-user MIMO

Long-Range Wireless

  • Standard antennas: Range of 40-50 meters
  • Long-range: Requires fixed directional antennas and regulatory compliance
  • Safety: Proper installation to avoid issues with power sources, weather, etc.

RFID Technology

  • RFID (Radio Frequency Identification): Used in access badges, inventory tracking, pet identification
  • Types:
    • Passive RFID: No internal power, powered by radar signal
    • Active RFID: Internal power source

NFC Technology

  • NFC (Near Field Communication): Extension of RFID used in mobile phones and smart watches
  • Uses:
    • Mobile payments
    • Device pairing
    • Access cards

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