Wireless Network Standards

Aug 21, 2025

Overview

This lecture covers the evolution of wireless network standards, focusing on the IEEE 802.11 family and related technologies like RFID and NFC, and summarizes key characteristics, frequencies, throughputs, and use cases.

Wi-Fi Standards and Evolution

  • Wireless networks follow IEEE 802.11 standards, often called Wi-Fi, a trademark of the Wi-Fi Alliance.
  • 802.11a (1999): 5 GHz, 54 Mbps, short range due to higher frequency absorption, rarely used today.
  • 802.11b (1999): 2.4 GHz, 11 Mbps, longer range but interferes with other devices (Bluetooth, phones, etc.).
  • 802.11g (2003): 2.4 GHz, 54 Mbps, backwards compatible with 802.11b, still subject to 2.4 GHz interference.
  • 802.11n (Wi-Fi 4, 2009): 2.4/5 GHz, up to 600 Mbps (4 streams, 150 Mbps each), supports wider 40 MHz channels and MIMO (Multiple Input, Multiple Output).
  • 802.11ac (Wi-Fi 5, 2014): 5 GHz, up to 6.9 Gbps (8 MU-MIMO streams at 867 Mbps each), supports wider 160 MHz channels and multi-user MIMO.
  • 802.11ax (Wi-Fi 6, 2021): 2.4/5 GHz, up to 9.6 Gbps (8 streams at 1.2 Gbps each), supports multiple channel widths, introduces OFDMA for crowded environments and improved efficiency.

Wireless Network Implementation Considerations

  • Standard home/office access points provide 40–50 meters range with built-in antennas.
  • Long-range or building-to-building connections require directional antennas, like Yagi, and signal strength adjustments.
  • Regulatory rules control frequency use, power limits, and indoor/outdoor transmissions; compliance is necessary.
  • Outdoor antenna installation requires safety precautions (e.g., distance from power sources, lightning protection).

RFID and NFC Technologies

  • RFID (Radio Frequency Identification) uses tags for wireless identification (access badges, inventory, pet tracking).
  • Passive RFID tags are powered by the reader's signal; active RFID tags have their own battery.
  • NFC (Near Field Communication) extends RFID for two-way mobile device communication (payments, device pairing, access control).

Key Terms & Definitions

  • IEEE 802.11 — A family of wireless networking standards set by the IEEE.
  • Wi-Fi — Trademark for certified interoperability of 802.11 wireless devices.
  • MIMO — Multiple Input, Multiple Output; multiple antennas for increased data throughput.
  • MU-MIMO — Multi-User MIMO; enables multiple users to access high bandwidth simultaneously.
  • OFDMA — Orthogonal Frequency Division Multiple Access; allows efficient channel sharing in dense environments.
  • RFID — Radio Frequency Identification; uses wireless tags for identification.
  • NFC — Near Field Communication; enables two-way communication between devices over short distances.

Action Items / Next Steps

  • Review differences among 802.11 standards and their appropriate use cases.
  • Know regulatory requirements for installing wireless networks, especially outdoor or long-range links.
  • Read about RFID and NFC applications in security and consumer technology.

Full transcript