IEEE g Standard Tim Wells Microcomputer Networks (CIS362) Thursday, April 28, 2005

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

Going Back In History… Before g There was: b a

IEEE Standard approved1997 Max Data Rate1-2 Mbps ModulationDSSS Frequency2.4 GHz had limited success due to low speeds and high prices.

IEEE b Standard approved1999 Max Data Rate11 Mbps ModulationDSSS + CCK Frequency2.4 GHz b greatly improved speed while maintaining compatibility with b 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 b products.

IEEE a Standard approved1999 Max Data Rate54 Mbps ModulationOFDM Frequency5.2 GHz a greatly increased speed, but decreased range. Even though the a standard was adopted in 1999, the first a products were not available until late a had a limited market response because of its incompatibility with b, shorter range, and higher costs.

IEEE g Standard approved2003 Max Data Rate54 Mbps (108 Mbps*) ModulationOFDM + CCK Frequency5.2 GHz g increased speed and range while maintaining compatibility with b. Even though g was not officially approved by IEEE until June 2003, products conforming to the draft were made available in late * With Atheros Super G

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

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

Range Comparison

802.11g Operating Modes

Can g 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

How does Atheros’ Super G make it faster? Frame bursting This allows a transmitting device to send multiple frames at once in a “burst”.

How does Atheros’ Super G make it faster? Fast Frames Fast Frames allows more information into each Frame

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 user’s involvement.