IEEE 802.11g Standard

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IEEE 802.11g Standard

• Tim Wells
• Microcomputer Networks (CIS362)
• Thursday, April 28, 2005

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What is 802.11g?

• IEEE Standard 802.11g is the latest Wireless
  Networking Standard that was created to increase
  range and speed while being compatible with the
  popular 802.11b.

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Going Back In History

• Before 802.11g There was
• 802.11
• 802.11b
• 802.11a

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IEEE 802.11
Standard approved 1997
Max Data Rate 1-2 Mbps
Modulation DSSS
Frequency 2.4 GHz
802.11 had limited success due to low speeds and
high prices.
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IEEE 802.11b
Standard approved 1999
Max Data Rate 11 Mbps
Modulation DSSS CCK
Frequency 2.4 GHz
802.11b greatly improved speed while maintaining
compatibility with 802.11. 802.11b products
received mainstream recognition as the first
wireless products with acceptable speeds,
affordable prices, and universal compatibility.
More than 95 of todays WLAN infrastructure
includes 802.11b products.
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IEEE 802.11a
Standard approved 1999
Max Data Rate 54 Mbps
Modulation OFDM
Frequency 5.2 GHz
802.11a greatly increased speed, but decreased
range. Even though the 802.11a standard was
adopted in 1999, the first 802.11a products were
not available until late 2001. 802.11a had a
limited market response because of its
incompatibility with 802.11b, shorter range, and
higher costs.
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IEEE 802.11g
Standard approved 2003
Max Data Rate 54 Mbps (108 Mbps)
Modulation OFDM CCK
Frequency 5.2 GHz
802.11g increased speed and range while
maintaining compatibility with 802.11b. Even
though 802.11g was not officially approved by
IEEE until June 2003, products conforming to the
draft were made available in late 2002.
With Atheros Super G
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What is CCK?

• Complementary Code Checking
• Was incorporated into DSSS beginning with 802.11b
  to increase efficiency.
• CCK is a single carrier system, meaning that
  all data is transmitted by modulating a single
  radio frequency or carrier.

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What is OFDM?

• Orthogonal Frequency Division Multiplexing
• Was first implemented in 802.11a.
• OFDM is a multi-carrier modulation scheme.
• Data is split up among several closely spaced
  subcarriers or frequencies, increasing
  reliability and speed

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Range Comparison
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802.11g Operating Modes
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802.11g Operating Modes
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Can 802.11g really get up to 108 Mbps?

• Yes, with Atheros Super G the maximum possible
  data rate is 108 Mbps, but the typical end user
  throughput is only 60 Mbps

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How does Atheros Super G make it faster?

• Frame bursting
• This allows a transmitting device to send
  multiple frames at once in a burst.

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How does Atheros Super G make it faster?

• Fast Frames
• Fast Frames allows more information into each
  Frame

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How does Atheros Super G make it faster?

• Compression
• Link-level hardware compression utilizes the
  connection more efficiently and maximizes
  bandwidth.
• Dynamic Turbo
• Dynamic Turbo can give a significant boost in
  bandwidth when required by demanding
  applications. It can trigger and double the
  apparent bandwidth by using 2 channels as one,
  without the users involvement.