802.11 Wireless Standards

Question 1

Wireless Standards

Answer 1

• Wireless networking (802.11)
• Managed by the IEEE LAN/MAN Standards
Committee (IEEE 802)

• Many updates over time
  
  • Check with IEEE for the latest
• The Wi-Fi trademark
  
  • Wi-Fi Alliance handles interoperability testing

Question 2

802.11a

Answer 2

• One of the original 802.11 wireless standards
  
  • October 1999
• Operates in the 5 GHz range
  
  • Or other frequencies with special licensing

• 54 megabits per second (Mbit/s)

• Smaller range than 802.11b
• Higher frequency is absorbed by objects in the way
• Many rules-of-thumb calculate 1/3rd the range of
802.11b or 802.11g

• Today, only seen in very specific use cases

Question 3

802.11b

Answer 3

• Also an original 802.11 standard - October 1999
• Operates in the 2.4 GHz range
• 11 megabits per second (Mbit/s)
• Better range than 802.11a - Less absorption problems

• More frequency conflict
• Baby monitors, cordless phones, microwave ovens,
Bluetooth

Question 4

802.11g

Answer 4

• An “upgrade” to 802.11b - June 2003
  
  • Operates in the 2.4 GHz range
• 54 megabits per second (Mbit/s)
  
  • Same as 802.11a (but a little bit less throughput)
• Backwards-compatible with 802.11b
• Same frequency conflict problems as 802.11b

Question 5

802.11n

Answer 5

• The update to 802.11g, 802.11b, and 802.11a
  
  • October 2009
• Operates at 5 GHz and/or 2.4 GHz
  
  • 40 MHz channel widths
• 600 megabits per second (Mbit/s)
  
  • 40 MHz mode and 4 antennas
• 802.11n uses MIMO
  
  • Multiple-input multiple-output
  • Multiple transmit and receive antennas

Question 6

802.11ac

Answer 6

• Approved in January 2014
  
  • Significant improvements over 802.11n

• Operates in the 5 GHz band
• Less crowded, more frequencies (up to 160 MHz
channel bandwidth)

• Increased channel bonding - Larger bandwidth usage
• Denser signaling modulation - Faster data transfers
• Eight MU-MIMO streams
  
  • Twice as many streams as 802.11n
  • Nearly 7 gigabits per second