Emerging Technology 802.11N: Wire's New Nemesis

802.11n is the emerging wireless local area network that is being widely

recognised as successor to the prevalent 802.11a/g. The wireless industry

expects 802.11n to revolutionise the scope of wireless LAN and take it beyond

its current appeal. Not only 802.11n promises a minimum throughput of 100 Mbps

(some vendors trying for 500 Mbps to 630 Mbps), it is likely to target markets

beyond home/enterprise networking and consumer electronics, segments that

802.11a/g now serves. Promoters of the standard believe that 802.11n will serve

markets like cellular telephony, mobile radio, personal computing, public

access, and VoIP. The ultimate promise of 802.11n: Let wireless systems replace

data-hungry wired networks such as those serving groups involved in

computer-aided design. According to the Institute for Electrical and Electronics

Engineers (IEEE), as enterprise networks in offices and campuses typically have

100 Mbps wired network connections, 802.11n will create parity between wired and

wireless systems, so enterprises can extend their wireless networks to areas

where the rate of existing wireless products has been insufficient.

However, 802.11n-based WLAN is unlikely to reach users until the beginning of

2006 as IEEE has still not finalised the standards and the industry is almost

vertically split on the specifics of standardization. Unlike 802.11a/g, 802.11n

is facing a divided industry largely on the issue of spectrum utilization. On

the one side is a group of companies called TGn Sync (Task Group n

Synchronization) and on the other is WwiSE (worldwide spectrum efficiency). The

leading companies in TGn Sync are Agere, Atheros, Cisco, Intel, Qualcomm,

Marvell, Nokia, Nortel, Panasonic, Philips, Samsung, Sanyo, Sony, and Toshiba.

WWiSE includes companies such as Broadcom, Conexant, Texas Instruments, Airgo,

STMicroelectronics, Bermai, and Realtek.

While both groups agree on the use of multiple input multiple output (MIMO)

antenna technology for taking 802.11n to its promised throughput, they disagree

on the use of channel bands. TGn Sync is for 40MHz channels in the 5GHz spectrum

(same as 802.11a). WWiSE supports 20MHz channels in the 2.4GHz (used by

802.11b/g).

Amidst all these, some vendors have begun shipping 802.11n products or are in

the process of doing so. Vendors like Agere and Atheros have released

consumer-oriented HDTV and video products based on the specifications that TGn

Sync supports. There is a new term for these pre-standard products-pre-802.11n.

While these products offer the speed and other benefits that 802.11n ultimately

promises and they might be backward compatible with 802.11b/g, they may not work

with the 802.11n based on the final standards. Buyers of these products could be

in for a raw deal. And this worrying Wi-Fi Alliance, and it recently asked

vendors not to move too fast on 802.11n. Arguing that the 802.11n standards

being developed by the IEEE are still not final, the alliance said it would be

difficult for it certify features based on the 802.11n unless the standards are

finally ratified. The alliance is not expecting the standards to be final for

the next two years. Its main argument is that releasing products based on

pre-802.11n would very much mean cheating the consumers. The alliance said it

would reserve the right to revoke the Wi-Fi certification of vendors' products

if they move too fast to introduce such features in a way that detracts from the

existing interoperability levels.

However, chip makers like Broadcom, one of the first to market with 802.11n's

predecessor 802.11g, have decide not to push its 802.11n chips to customers

until the IEEE is closer to final standardization.

Source: Voice & Data  For More: http://www.voicendata.com/content/goldbook/goldbook05/105030520.asp