The upcoming IEEE 802.11n standard, promoted as the key to wirelessly sharing high-quality multimedia content throughout a home, still faces some speed bumps on the way to making that vision a reality.
Vendors don’t know how they will handle the two radio frequency ranges that 802.11n will support; they’ll need some other standards to work alongside it, and the unlicensed spectrum used for Wi-Fi may simply not be able to support a service provider’s commitment to deliver high-quality content to subscribers, according to various participants in a panel discussion Wednesday at Intel Developer Forum in San Francisco.
The 802.11n standard, still under discussion in a working group of the Institute of Electrical and Electronics Engineers, can be used in both the 2.4GHz radio band currently used for 802.11b/g and the 5GHz band in use now for 802.11a. It also is intended to be backward compatible with those existing specifications while delivering greater range and real throughput of 100Mbps (megabits per second), twice or more the speed of the current technologies. A compromise between two warring camps led to a draft standard in January, probably leading to final approval in about a year.
However, it’s not yet certain how 802.11n networks will use the two frequency bands, according to vendor executives on Wednesday’s panel. The standard could mandate that every product have radios for both bands or allow companies to sell 802.11n products that work in just one band, according to Miguel Pellon, vice president of technology standards at Motorola Inc., in Schaumburg, Illinois.
The 2.4GHz band would provide backward compatibility with 802.11b/g, the most common technology in home wireless LANs today, but it also faces more interference from existing wireless LANs as well microwave ovens and Bluetooth short-wave wireless connections, said Yoshiharu Doi, a manager at Sanyo Electric Co. Ltd. who represents Japanese consumer electronics vendors in the 802.11n standardization process. For that reason, the Japanese companies have decided it’s not ideal for entertainment applications such as high-definition video streams, Doi said. He envisions 802.11n products being able to shift between the two bands, moving to 5GHz for those highly demanding uses.
Automating that process is critical to the technology’s success, said Phil Kearney, director of communications technology for Mac hardware at Apple. Ordinary consumers don’t want to deal with it themselves, he said.
“My mother will hit me on the side of the head with a wooden spoon if I start mentioning ‘2.4’ and ‘5’ to her,” Kearney said.
The new standard can’t support high-quality video streams by itself, either, according to Mark Grodzinsky, product manager for wireless products at Intel Corp. That feat will also require several other pieces, including the 802.11i standard for security and 802.11e for guaranteed quality of service, as well as the Wi-Fi Alliance’s quality-of-service specification, WMM (Wi-Fi Multimedia). However, all those will be available when 802.11n products hit the market, he said.
In any case, service providers that want to use Wi-Fi to deliver multimedia content around the homes of their subscribers will have a hard time making the service assurances they are used to offering, according to Alan Cohen, senior director of product management for Cisco Systems Inc.’s Wireless Networking Business Unit. Because Wi-Fi operates on unlicensed frequencies, it can’t deliver the same kind of guaranteed performance that carriers expect when they use wired technologies or licensed spectrum, Cohen said.
U.S. cable operator Comcast Corp. is still examining ways to deliver television and other content throughout its subscribers’ homes, according to Comcast Fellow Mark Francisco, who asked the panel about using 802.11n for a “service-assured” offering. There are wired distribution technologies, such as the HomePlug home power line system, that customers could deploy without a visit from Comcast technicians, he said. The company might also use a combination of wired and wireless where appropriate, he added.
This story, "IDF: Hurdles remain on road to faster Wi-Fi" was originally published by PCWorld.