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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.
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