Proprietary Extensions to the IEEE 802.11g Standard

Although IEEE 802.11g is the fastest IEEE wireless network standard at present, it is frequently referred to as the slowest wireless network standard at many retail stores. This is because most vendors have created various extensions to the IEEE 802.11g standard in a drive to improve network performance and to sell more expensive network adapters, APs, and so forth. Proprietary extensions fall into the following categories:

• Network hardware promising faster throughput

• Network hardware offering greater range

Two major technologies are designed to improve IEEE 802.11g transfer rates: Atheros Super G and Broadcom Afterburner. Atheros and Broadcom are chipset vendors, not network adapter vendors. However, between them, almost all wireless network vendors offer one or the other speedup technologies as part of their product lines. Table 21.2 compares the major features of these technologies.

Table 21.2. Faster-than-802.11g Technologies Compared

Feature	Atheros Super G	Broadcom Afterburner
Claimed top speed	108Mbps	125Mbps
Claimed improvement over 802.11g (54Mbps)	2x faster than 802.11g	2.3x faster than 802.11g
Method used for speed improvement	Channel bonding using two non-overlapping channels; can automatically revert to a single channel when another wireless network causes interference	Reduced signaling overhead; combines packets
Vendors supporting the technology	D-Link (AirPlus Xtreme G) and Netgear (108Mbps)	Belkin (Wireless G Plus), Buffalo (AirStation 125), Linksys (SpeedBooster), and US Robotics (Wireless Turbo 125)

Although the real-world throughput of these products is considerably lower than the stated speeds, both types of products do provide about a 30%35% boost in real-world throughput over standard 802.11g hardware. For best results, products from the same vendor, or at least using the same chipset, should be used on a single network.

The second type of improvement over standard IEEE 802.11g hardware involves improvements in range, often combined with speed improvements based on the technologies listed in Table 21.2.

Table 21.3 compares range-improvement technologies used by major wireless network vendors. Most use some form of multiple in, multiple out (MIMO), which uses multiple antennas in various ways.

Table 21.3. Range Improvements Technologies for Enhanced 802.11g Networks

Vendor	Technology	Used By	How It Works	Notes
Airgo Networks	True MIMO	Belkin Pre-N, NETGEAR Pre-N, and Linksys SRX	Two sending antennas in the router send unique streams of data to three receiving antennas in the True MIMO client.	Helps improve range and performance for standard 802.11g clients as well.
Atheros	Super G MIMO	D-Link Super G MIMO	A pair of smart antennas send data directly to the antennas of the Super G MIMO client.	Based on Super G.
Video54	BeamFlex	NETGEAR RangeMax	Seven internal antennas are used in various combinations to transmit data directly to the device or to reflect signals off obstacles.	RangeMax network clients also have multiple antennas and optimized software.
Broadcom	BroadRange	U.S. Robotics MAXg	Router and clients feature higher signal strength and more sensitive receivers than previous versions.	Shorter range than MIMO-based solutions; not suitable for long-distance (outdoors) use.

Note

Airgo claims that the definition of MIMO involves techniques such as beam forming, receive combining, and multiplexing along with multiple antennas. Other vendors, such as Atheros and Video54, use MIMO to refer to other methods of using multiple antennas. At this point, there is no legal definition of MIMO, so different vendors are free (for now) to use (and argue over) the meaning of MIMO.

Because these methods have been developed by chipset and technology vendors rather than by network adapter manufacturers themselves, you might see other vendors adopt various combinations of these technologies in the future.