802.11n Working In Progress

The promise of improved performance and speed from the next generation of Wi-Fi, 802.11n, eventually should be an incredible benefit to home and business wireless network users. The speed of 802.11n will make current wireless networking standards seem as though they’re working through a strong headwind. 802.11n will be key in developing home networks, such as allowing for the sharing of high-def files among components on the network.

There’s much to like about 802.11n, other than one problem: the IEEE (Institute of Electrical and Electronics Engineers) may not ratify the final specification until the second half of 2007. Until then, those wanting 802.11n have two choices: 1) Wait 2) Purchase “pre-standard” equipment, gain some of the benefits of 802.11n now, and hope that the hardware will still work with the final standard.

It’s your standard risk-reward question: Is the risk of whether the new technology will work as expected in the future worth the reward of spending money on it now?

The 802.11n standard should provide better reliability and range along with larger bandwidths, thanks to the use of MIMO technology. MIMO (Multiple Input/Multiple Output) is a vital part of the improvements that will be available through 802.11n. Implementation of MIMO technology should alleviate some of the problems often found with wireless networking, including signal fade, interference, and limitations with the available spectrum. It will help prevent “dead spots” within home or business environments that often occur with today’s wireless standards.

MIMO technology also will allow a 40MHz bandwidth for 802.11n vs. the 20MHz bandwidth 802.11g and 802.11b use. However 802.11n will draw on the same technology, called OFDM (orthogonal frequency division multiplexing), that 802.11g uses to improve performance and will be backward compatible with previous 802.11 wireless technologies.

Many of the industry’s top companies supported several groups that began the original work on the 802.11n standard. The groups, along with a few individual companies, offered numerous proposals regarding the specifics of 802.11n. TGn Sync and WWiSE, however, soon emerged as the leading contenders to develop the final 802.11n standard.

TGn Sync’s initial supporters list included Intel, Atheros, Agere, Cisco, Infineon, Mitsubishi, Nortel, Panasonic, Philips, Qualcomm, Samsung, Sanyo, Sony, and Toshiba. WWiSE received the backing of Texas Instruments, Airgo Networks, Bermai, Broadcom, Conexant, and STMicroelectronics. Motorola also koined the WWiSE camp after its own 802.11n proposal failed to garner enough support, and Nokia later switched from supporting TGn Sync to WWiSE.

The proposals from both groups were similar: Use MIMO as the base technology. Both proposals also supported backward compatibility with older wireless networking standards. However, neither group’s proposal individually received enough support in the IEEE voting in early 2005 to find a clear-cut leader.

After more than a year of jockeying for position and adding various companies in each camp, TGn Sync and WWiSE eventually chose to work together. The two groups formed the JP (Joint Proposal) team and submitted a combined plan in the second half 2005 to the IEEE. But that proposal hit a slight bump in the road when Intel, Atheros, Broadcom, and Marvell chose to form a breakaway group called EWC (Enhanced Wireless Consortium), which planned to bypass the IEEE to form a standard more quickly. Leading Wi-Fi equipment makers and consumer electronics leaders, including 3Com, Apple, Buffalo, Cisco, D-Link, Lenovo, Linksys, Netgear, Sony, Symbol, Toshiba, and US Robotics, also joined EWC. EWC announced plans to boost Wi-Fi transmission speeds to 600Mbps in short order, which was even more than the 100 to 150Mbps intended with the 802.11n standard.

After meetings late in 2005, though, those companies in the EWC decided to work with the JP team within the IEEE 802.11n framework toward a single proposal. The JP team decided to adopt the majority of the EWC specification for submission to the IEEE in January 2006.

Within a few weeks of the decision to send the EWC specification to the IEEE, companies were already testing 802.11n products. These types of prestandard product releases have become more common in recent years for several technologies. Such products are built to the specification as it is submitted to the governing body (the IEEE). However it sometimes means the pre-standard product appears a year or more before the governing body ratifies the standard. Many pre-standard 802.11n products began to appear on the market in the first quarter of 2006. (MIMO-based products actually have been around for a couple of years but only focus on using MIMO technology and don’t necessarily involve other aspects of 802.11n.) Obviously such products give users the benefits of the new standard immediately, and most work with all existing 802.11 wireless standards.

Pre-standard 802.11n products may carry some risk to the user, though. Without a ratified standard to work from, hardware from one manufacturer might not work at top efficiency or with another manufacturer’s hardware. It’s also possible that some hardware designed for use with the 802.11n draft standard will interfere with any hardware using the 2.4GHz wireless band.

If the standard undergoes any kind of changes before ratification, it’s possible the pre-standard equipment won’t work with the hardware that’s certified to use the standard. In some cases, the users can later upgrade the pre-standard hardware with firmware, but the reworked hardware still might not have all of the top-end benefits and features that the post-standard equipment will have. In other cases, users may not be able to upgrade the pre-standard equipment with firmware at all.

The other potential problem involved with 802.11n pre-standard product concerns the standard itself. When the standard was up for vote from the IEEE in April/May 2006, it reportedly received an extremely large number of comments from IEEE members – about six times as many comments as standards typically receive - meaning there were plenty of IEEE members questioning some aspects of the initial standard. Less than 50% of the membership voted to adopt the standard in its initial form. Any specification submitted to the IEEE engineers eventually must receive a 75% supermajority of favorable votes for adoption.

What the large number of comments probably meant is that the final standard may not appear for at least another 12 to 18 months, as it may need to undergo some significant changes before ratification. Ultimately each user will need to decide whether the potential benefits of pre-standard 802.11n products are worth the potential risk down the road. The improved wireless networking speed and reliability of these products are definitely tempting, and with big-name companies offering the pre-standard hardware, the temptation may be too difficult to ignore for many people.