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WiMax making its mark as Wi-Fi's big brother

Posted: 19 Apr 2004 ?? ?Print Version ?Bookmark and Share

Keywords:wimax? wireless? dsl? intel communications alliance? cable?

Gupta: WiMax is a four-to-five year project.

WiMax is no more a mere blip on the wireless radar while Wi-Fi revolution unfolds right in front of our eyes. Wi-Fi's big brother - as Mark Johnston, Asia-Pacific director for Intel's communications and marketing and sales - likes to call it, broadband wireless access technology has emerged as a dramatic trend and is increasingly seen as a replacement to DSL and cable on many fronts.

"WiMax is still in its infancy, but we see the same kind of transformation spirit we have witnessed in the Wi-Fi space," Johnston said at a recent Intel Communications Alliance conference in Bangkok.

Shantanu Gupta, director of marketing at Intel Communications Group, said in his keynote that WiMax is a next four-to-five year project and will have multiple usages.

It will be implemented first as the fixed outdoor access solution for Wi-Fi backhaul traffic among base stations and then you have last-mile option purely aimed at high-speed data connections. WiMax as a wireless access point for indoor use will be the next frontier, according to a roadmap outlined by Intel's Gupta.

Finally, you will have WiMax with true mobility at speeds of up to 70mph. "While Wi-Fi is available for indoor applications, the reason you could use WiMax is that it allows you mobility," Gupta said. "With Wi-Fi, you lose the signal when you move out of that area."

WiMax standard has multiple profiles. The 802.16d spec for fixed outdoor is final, while 802.16e spec for walking mobility has also been finalized. True mobility with IEEE 802.20 mobile broadband wireless access spec at vehicle speeds is still under development.

Technical challenges

Gupta acknowledges that WiMax is still many years away from overcoming challenges of line-of-sight, bandwidth and topography. He reckons the silicon for fixed outdoor will be available late this year, added with some indoor capability by the end 2005. In 2007 or 2008, you may see silicon for handsets and PDAs.

Responding to the confusion regarding mode of WiMax transmission, Gupta said initially it'd be point-to-point communications with need to have line-of-sight. "But when a WiMax tower or hub is beaming to multiple access points, then it's point-to-multipoint within an area of 30 square miles."

Interference is going to be another issue as WiMax shares the same unlicensed portion of radio spectrum with upcoming wireless technologies like Mobile-Fi, ZigBee and Ultrawideband.

"There is the potential for interference between Wi-Fi and WiMax, particularly in outdoor Wi-Fi, which often operates at a higher band than indoor Wi-Fi," said Tim Crowley, senior analyst for broadband markets and technologies at IDC Asia/Pacific. "That brings greater possibility of interference as outdoor Wi-Fi may operate closer to WiMax bands."

Peaceful coexistence

Wi-Fi and WiMax are not competing technologies from a market standpoint. In fact, some industry observers believe that the continued expansion of Wi-Fi will likely benefit future commercial WiMax deployments.

"The two technologies are complementary in many ways, and one of the areas where WiMax looks promising is as a backhaul connection for wireless LAN networks," said Crowley.

On the other hand, he added that it's important that the bodies pushing Wi-Fi and WiMax work closely together to make sure the complementary nature of the two stays such.

There will certainly be critical issues in the coexistence between Wi-Fi and WiMax. Battery life and having multiple antennas in the device are the most notable ones. "We've already seen the high power usage in Wi-Fi and this is a continual challenge in pushing out new access devices, particularly small, consumer devices," Crowley said.

However, he says that it's a question of figuring out some engineering solutions, which will likely come aboard with time and research.

Power handling

But before that, according to Intel's Gupta, we have to see things from usage perspective. "Once the usage patters become clear, there are ways to get over the power issues," he said.

First is power management at the silicon level; you create silicon that consumes less power. Second, we integrate silicon building blocks, so instead of having six pieces of silicon, you have only two. Third is translating MEMS into silicon, so passive components in radio that take significant amount of power are implemented in silicon.

"Once people figure out at the usage level, the next step is to sort out coexistence within the device," Gupta added.

Initially, he said, we will have unique pieces of silicon implementing Wi-Fi, WiMax and cellular. The ultimate answer for converged devices is what we call cognitive radio, one that can sense its environment and location, and then alter its power, frequency, modulation and other parameters so as to dynamically reuse available spectrum.

Today we have multiple versions of Wi-Fi that are evolving; WiMax is on the horizon; and 3G exists in certain geographies. We can imagine devices operating in a multiple-standards environment in which multiple user experiences are based on right value of the content. WiMax is fast becoming an important facet of this wireless ubiquity.

- Majeed Ahmad

Electronic Engineering Times-Asia





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