Wireless Network Standards 2.3

Sep 3, 2024

Lecture Notes: Wireless Networking and IEEE 802.11 Standards

Introduction to Wireless Networks

  • Wireless networks are common in homes, businesses, restaurants, and conference rooms.
  • Standards for wireless networks are governed by the IEEE 802.11 standard.
  • Wi-Fi is the trademark from the Wi-Fi Alliance, responsible for interoperability testing.

IEEE 802.11 Wireless Standards

802.11a

  • Released in October 1999.
  • Operates in the 5 GHz frequency range.
  • Maximum speed: 54 Mbps.
  • Less common today, often upgraded to newer standards.

802.11b

  • Released at the same time as 802.11a.
  • Operates at 2.4 GHz frequency with a maximum speed of 11 Mbps.
  • Offers longer range than 5 GHz due to signal bouncing.
  • Frequency conflicts with devices like baby monitors and Bluetooth.

802.11g

  • Released in June 2003.
  • Operates at 2.4 GHz with speeds up to 54 Mbps.
  • Backwards compatible with 802.11b.
  • Suffers from the same frequency conflicts as 802.11b.

802.11n (Wi-Fi 4)

  • Released in 2009.
  • Operates in both 5 GHz and 2.4 GHz ranges.
  • Supports channel widths up to 40 MHz.
  • Introduced MIMO (Multiple Input Multiple Output).
  • Maximum theoretical throughput: 600 Mbps.

802.11ac (Wi-Fi 5)

  • Released in January 2014.
  • Operates only at 5 GHz.
  • Supports up to 160 MHz channel bandwidth.
  • Introduced MU-MIMO (Multi-User MIMO).
  • Maximum theoretical throughput: 6.9 Gbps.

802.11ax (Wi-Fi 6)

  • Released in February 2021.
  • Operates at both 5 GHz and 2.4 GHz frequencies.
  • Supports multiple channel bandwidths (20, 40, 80, 160 MHz).
  • Introduced OFDMA for better performance in crowded areas.
  • Maximum theoretical throughput: 9.6 Gbps.

Special Considerations for Wireless Networks

  • Range of typical access points is about 40-50 meters.
  • For long-range connections, directional antennas like Yagi are required.
  • Regulations may apply regarding frequencies and signal strength.

RFID and NFC Technologies

RFID (Radio Frequency Identification)

  • Used for access control, inventory tracking, and pet identification.
  • Typically passive, using antenna to capture power for transmission.
  • Active RFIDs have a power source.

NFC (Near Field Communication)

  • Used in mobile phones and smart devices.
  • Facilitates contactless payment and Bluetooth pairing.
  • Can be used as an access card replacement.