Tuesday, December 15, 2009

7Gbit/s can be delivered at 60GHz spectrum

From TechWorld:

The Wireless Gigabit Alliance has completed its specification for a technology to deliver as much as 7Gbit/s over a very high unlicensed frequency band.

The group, backed by wireless heavy hitters including Intel, Broadcom and Atheros Communications, announced the WiGig specification in May and said it would be finished by year's end. Though the standard is now written, it's still undergoing text editing and an intellectual-property review that the WiGig Alliance called routine.

WiGig was designed for very high speeds over a relatively small area, using the 60GHz band. It will have the capacity to deliver high-definition video streams or let users connect laptops to desktop docks and displays, the group has said. It will come to the fast home-networking market behind a few other technologies, including HomePNA, HomePlug, Multimedia over Coax, Ultrawideband and Wireless Home Digital Interface. However, WiGig's strong backing and relationship to Wi-Fi seem likely to give it a major boost.

The WiGig Alliance had said in May the specification would be available to members in the fourth quarter. It is available now to the member companies that helped develop it, but the group hasn't yet created its Adopter membership for companies that will simply use the technology, said Ali Sadri, chairman and president of the group. That will happen in the first quarter of next year, and the specification will be made available to them then. The group will set up a certification system next year and expects consumer products with WiGig to start hitting the market in 2011.

The group originally had said WiGig would have a top speed of about 6G bit/s but has raised that estimate. At that speed, WiGig will have about 10 times the capacity of the fastest Wi-Fi technology today, a form of IEEE 802.11n that offers 600Mbit/s. The 7Gbit/s figure represents the theoretical maximum speed, but the technology is highly efficient, so users should be able to use at least 80 percent of that bandwidth in the real world, Sadri said. On a WiGig LAN, the bandwidth would be shared among all the users on an access point.

Along with the completion of the specification, the WiGig Alliance said it has included a "beam-forming" feature that should allow WiGig networks to work over distances greater than 10 metres. Radios using high frequencies such as 60GHz fundamentally have a harder time transmitting data over long distances without repeaters. WiGig originally was envisaged as an in-room technology, but with the beam-forming feature it could more easily send data and content around a home.

The high 60GHz frequency at which WiGig runs is unlicensed in many parts of the world, including the U.S. The Wi-Fi Alliance is also developing a standard for high-speed wireless LANs at 60GHz, called IEEE 802.11AD, but the Wi-Fi Alliance has said WiGig seems to be complementary to Wi-Fi. Intel, Broadcom and Atheros all plan to integrate WiGig into Wi-Fi chipsets, and it could become part of a "tri-band Wi-Fi" that would let users migrate to WiGig for additional speed where it's available.

The WiGig specification was written so that it could be made an amendment to the 802.11 standards, with backward compatibility, Sadri said.

All WiGig equipment will be able to communicate at the basic level of exchanging IP (Internet Protocol) packets, but the alliance is also developing protocol adaptation layers to optimize the performance of specific applications, said Mark Grodzinsky, marketing chair of the WiGig Alliance. For example, any two WiGig products will be able to stream video to each other, but with a special protocol adaptation layer they might be able to do it with less delay and without compression, he said.

The WiGig Alliance has also announced that Nvidia, Advanced Micro Devices, SK Telecom and TMC, an independent testing and certification lab in China, have joined the group of about 30 companies.

For details see: http://wirelessgigabitalliance.org/


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