IEEE groups fight for control of key standards
New divisions in 802.11n:
Also in Wi-Fi, further divisions have arisen in the quest for a fast version of the standard. We have already outlined the division over the technological approach that should underpin the next extension to Wi-Fi, 802.11n, which will specify networks operating at over 100Mbps (see Wireless Watch issue 69). Now, challenging the two main groupings, led respectively by Atheros and Airgo, is chipmaker Agere, which has thrown the cat among the pigeons, claiming the real goal of the standard should be 500Mbps data rates.
The company says its proposal combines MIMO (multiple in multiple out) smart antennas with single 20MHz or double 40MHz channel widths. The full 500Mbps raw throughput is achieved by using the maximum number of antennas – four at each transmitter and receivery – and the wider channels. The technology would offer backwards compatibility with 802.11b/g and would also support two-antenna configurations for lower cost products at lower speeds.
The company has been working on wireless MIMO technology for some years and in 2002 demonstrated a 162Mbps three transmitter/three receiver MIMO system.
Agere would not provide details of when working silicon would be available to demonstrate its proposed 500Mbps 802.11n capability. It said the flexibility to support single or double-width channels not only made it suitable for all countries – Japan specifies 20MHz channels for WLans, for instance – but also allowed for a configuration in 2.4GHz. While 5GHz would be required for the full 500Mbps, the lower frequency support would allow for coexistence with 802.11b/g.
Another feature of the submission is a standardized frame aggregation for both single and multiple destinations, to improve network efficiency and interoperability. Frame aggregation, - which merges several frames together in a single packet, - is important for streaming applications including voice over IP and multimedia content.
The road to harmonization
All these disputes are to be expected in a wireless world that is so newly formed and where all the technologies and standards, and many of the players, are immature. Some of them, like the 802.11n and 802.15.3a splits, do raise important issues of functionality, but are primarily about vendor bids for control and royalties.
Others, like the arguments over whether to unify 802.16, 802.20 and Wi-Bro, while political, are also centered on fundamental debates over the role of the various standards in the real world. Should there be separate standards for portable, metro area wireless and highly mobile networks, or should these be merely different variations of the same base?
There are technological and market arguments on both sides, even if the final outcome is likely to be decided by the needs of the big vendors, like Intel, to support as broad and powerful a standard as possible. What the current IEEE meeting also highlights is the dilemma created by the very speed of wireless technology development.
Rapid uptake of Wi-Fi has attracted hundreds of suppliers, all seeking to survive, and to maintain margins, by stretching the technology a step further and gaining differentiation from their rivals. This cycle of price wars and new product developments is more rapid than we have seen anywhere before in the communications sector and, while it fosters innovation, it also creates huge problems for standards bodies and therefore for operators’ and enterprises’ longer term planning.
If Wi-Fi can move out of its LAN space and achieve 100 miles per hour mobility, 500Mbps data rates and extended range, why do we need WiMAX? If WiMAX can reach beyond its metro area remit and become fully mobile, what is the point of 802.20? And that’s not to mention the cellular technologies still determined to hold on to their massive market lead in wireless communications.
The answer, of course, comes back to harmonization, effective integration and the much vaunted cognitive radio, all of which will make the choice of standards less critical and will allow devices to take advantage of the different benefits of all those available. Reduce the list down to 802.11, 802.16, 802.15 and cellular, and allow users to access all of them on an always best connected basis, and we are coming close to the ubiquitous wireless world touted by the equipment makers and Michael Powell.
In this picture, the cognitive radio becomes the most vital wireless development of the coming few years , and the mooted 802.22 committee perhaps the most important of all within the IEEE. Which finally makes it very clear why the WiMAX brigade are so keen to bring that effort under their auspices.
Upcoming IEEE standards
The next Wi-Fi standards in line to be ratified are 802.11e for quality of service, later this year, followed in the 1-2 year timeframe by 802.11n for 108Mbps speeds, 802.11r for fast hand-off between access points, and 802.11s for mesh networking.
Further down the track is 802.11p, and further taskforces are mooted for performance prediction for testing (likely to be 802.11t) and interworking with external networks. It is also possible that a standing committee will be formed to look at security issues on an ongoing basis, especially to ensure that these new extensions do not involve new security problems, and there is also the 802.11m standing committee, for standards maintenance.
For 802.16, the next priorities are the mobile 802.16e, tabled for late this year, and an 802.16f extension addressing mesh using directional antennas, slated for late 2005.
For personal area networks, the fight drags on to choose the base for the 802.15.3a standard, a higher speed, UWB-based extension to 802.15.3 or WiMedia. While 802.15.3 addresses high data rate, short range networks, its cousin 802.15.4 or ZigBee looks at low data rate, low power equivalents. Its current major project is an ‘a’ extension of its own, also based on UWB.
Copyright © 2004, Wireless Watch
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