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Fujitsu plans 802.16a IC for metro wireless netsBy Anthony Cataldo
Approved by the IEEE last January, the 802.16a is being touted by supporters as the first standard wireless metro-area network to link 802.11 hot spots to the Internet. Among the key attributes of the fixed-point wireless standard are its long 20-kilometer range, inherent quality-of-service features and its ability to make connections without having a direct line of site.
Some proprietary wireless MANs serving this purpose have already started cropping up in China and other parts of Asia. Fujitsu and other like-minded chip makers hope wireless systems companies will eventually adopt 802.16a so that they can sell standard devices in high volumes.
"What 802.16 allows us to do is consolidate under a common air interface, just as 802.11 consolidated under that interface," said Aditya Agrawal, senior marketing manager at Fujitsu Microelectronics America Inc. "Similarly with .16, we hope to bring down the price point of fixed wireless access solutions."
Fujitsu is currently developing a 802.16a device that integrates both the physical and media access control layers (MAC), which will include an ARM9 processor. Based on 0.18-micron design rules, the chip should be ready by early next year. Pricing is has not been determined, though the final system price tag should not exceed $300, Agrawal said.
Fujitsu will work with multiple providers of RF front-end devices and recommend those that are compatible with its device. Because of its extended range, the 802.16a systems should consume more power and require more advanced antennas than typical WLAN systems. Fujitsu will offer a reference design with component recommendations when its combination PHY/MAC chip is formally introduced, Agarwal said.
Fujitsu plans to make a presentation on 802.16a and discuss its product roadmap at the Broadband Wireless World Conference in San Jose, Calif. on April 10.
Whether the market will rally behind 802.16a is still a question. One possible hurdle: some are proposing that the entrenched 802.11 standard can evolve as an air interface for MANs. Another possibility is that 802.16a will wind up being subsumed by 802.11 if that standards group fails to come up with a workable quality-of-service scheme of its own.
Fujitsu, however, is trying to make the case for 802.16a as the right path to creating wireless MANs. The 802.16a spec, for one, uses a 256-point orthogonal frequency division multiplexed (OFDM) carrier technology, giving it greater range than wireless LANs, which are based on 64-point OFDM. Another key difference of 802.16 is its use of time slots, allowing greater spectral efficiency for quality of service capabilities, Agrawal said.
"The .16 proponents realize that .11 is a LAN technology. If you have more users, for example, and are trying to transmit, then the packets collide and every one of them would have to back off. There's no pre-set scheme for quality of service," he said.
What could also fuel support for 802.16a is that it can operate in the same single-carrier OFDM mode of the analogous HiperMAN standard in Europe. Agrawal said there have been "liaison efforts" between those backing the IEEE version and the European Telecommunications Standards Institute, which oversees HiperMAN. Asian OEMs are expected to adopt either, he added.
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