Jim:
Will OFDM Run CDMA off the Road?
By Ruth Suarez
From the February 5th edition of Wireless Insider
Imagine paying top dollar for the leanest and meanest car on the market and no sooner having walked off the lot getting dust kicked up in your face with next year's shinier model. And it only costs a tenth of what you paid. And you were already in debt before walking onto the lot.
Those tears of frustration may soon be welling in the eyes of telecom heavy-hitters that are bidding top dollar on spectrum licenses.
That new car speeding by third-generation wireless dreamers may be orthogonal frequency division multiplexing also known as OFDM.
The technology, which promises to overcome signaling transmission barriers and step up transmission speeds is being pushed along by San Jose, Calif.-based Cisco Systems [CSCO], Bedminster, N.J.-based Flarion Technologies, a Lucent Technologies [LU] venture and Calgary, Canada-based Wi-LAN Technologies.
While telecom equipment giants can be ruthless when it comes to plugging their flavors of a standard, they aren't the ones to blame, says Andy Fuertes, vice president of communications in electronics research for Oyster Bay, N.Y.-based Allied Business Intelligence, a telecom consultancy.
"What really becomes a factor is greed," Fuertes says. "The greed of regulating bodies both domestic and abroad. The FCC and its equivalents are forcing a large amount of debt on these carriers. They are pushing them into a market concept that is untested."
The lofty $16.9 billion price tag on the U.S. C- and F-band auctions raises debt-ridden carrier expectations on seeing returns on their investment in the not-too-distant future. But the entrance of new technologies threaten to sour those expectations.
"Some of these operators are going to take a beating," says Christine Stasikowski, an analyst with Washington-based Strategis Group, a wireless research firm.
Those operators are hoping to capturethe estimated 9.4 million wireless broadband subscribers expected to flood the market by 2005, up from the approximately 200,000 users today, according to Allied Business Intelligence.
"The mention of OFDM is running contrary to those who've invested in CDMA," Fuertes says.
There is debate in the industry as to whether OFDM could push aside CDMA and work its way into third-generation networks or get elbowed into the world of yet another wireless network generation: 4G.
"Pushing OFDM to 4G is risky since the prospect for 3G is not as bright as expected," Fuertes says. "The business model of a carrier making a profit off of 3G has been unproven."
New Model Perks
OFDM is a signaling scheme that divides a digital signal across 1,000 or more signal carriers simultaneously. The capability to work around interfering signals, is one of the most lucrative of a technology that threatens CDMA technology. That talent is pushing the technology forward in Europe. In densely populated areas where buildings, trucks, people and geographic protrusions can scatter the path of a signal, broadcasters as well as high-speed data providers are anxious to eliminate multi-path effects.
"It's a wonderful technology that transmits larger amounts of data and provides greater security for that data," says Stasikowski.
"This is very attractive to a hostile communications environment," Fuertes says. "This shows resistance to multipath interference. It definitely has strong benefits."
According to industry analysts, carriers also may be lured to the technology because it could end up causing only a fraction of what it costs to implement third-generation technologies. While it all sounds great for the industry, it's a big thorn in the side of carriers and vendors that already have invested in CDMA technologies, which they anticipate will take them into the third-generation world of wireless services.
"[OFDM] is very promising," says Paul Kellett, senior director of research for Boston-based Pioneer Consulting, a broadband telecommunications research firm. "If it [OFDM], in fact, becomes widely deployed, it will represent an opportunity to reach much higher levels of penetration than we otherwise would," Kellett says. "What it offers, above and beyond other technologies, is the ability to overcome the obstacle resulting from interference."
OFDM helps the line-of-site issue because the transmission overcomes roadblocks and makes fixed wireless services available to a greater portion of the population.
While OFDM is wreaking havoc in the once-tranquil 3G wireless world, it is garnering wide acceptance in the broadband fixed wireless arena.
Already, OFDM is the basis for the high-speed wireless LAN standard dictated by the Institute of Electrical and Electronics Engineers' 802.16 workgroup.
The technology already has gained notoriety in the wireless LAN space as an effective way to get around multipath. Since OFDM allows data to be encoded on multiple high-speed radio frequencies, it ensures a high degree of security, increases the amounts of sent data and is the most efficient use of bandwidth in the industry, according to Stasikowski.
Politics Fueling Race
While OFDM technology is unique, politics surrounding it aren't.
Like most political wrangling, there's more than one side to the issue. It's OFDM against third-generation proponents and fighting within the OFDM clan, wherein vendors are pushing their own technology flavors.
"We've got two alliances fighting for their own particular version of that access technology," Keller says. "The whole issue of standards has been dragging on for some time now. How quickly it will be resolved remains to be seen."
In Wi-LAN's OFDM, the carrier spacing is large enough so that frequency errors between the transmitter and receiver are only a fraction of the spacing, making the spacing negligible on the system performance.
According to Stasikowski, recent tests of Wi-LAN W-OFDM technology achieved data rates of 30 Mbps while traveling at 70 mph speeds. Thirty Mbps exceed the 10 Mbps the industry expects from 4G systems.
The downside for these three vendors is network operators that were prepping for 3G networks would have to deploy new infrastructure. "Thus its adoption may have to wait until carriers look past 3G systems to 4G," Stasikowski says.
Wi-LAN, however, contends that the cost of deploying its W-OFDM network will cost 10 percent of 3G deployment costs.
Flarion Technologies is propagating Flash-OFDM, a wideband approach aimed at mobility applications in cellular networks. The technology would enable frequency diversity and the benefits associated to the averaging out-of-cell interference, according to Stasikowski.
Cisco's VOFDM improves the multipath by using spatial diversity with OFDM. Analysts applaud the technology for improving reception and processing signaling with scale. Cisco, one of the telecom equipment vendors carefully dodging Wall Street beatings, has been massaging its standard into the industry for some time now. Cisco steered the VOFDM Consortium in 1999, prior to the OFDM Forum's spring 200 existence.
But tentative telecom players weren't ready to give more market share to the telecom equipment giant.
"A lot of resistance to Cisco's flavor was political," Fuertes says. "A lot of them didn't like the idea of the market being defined by Cisco."
Hitting the Pavement
Already, service providers that are using OFDM attest to its speed.
T-Speed Broadband Communications Inc., a fixed wireless high-speed broadband Internet service provider, signed a three year contract with Wi-LAN.
T-Speed advocates whatever gets its customers fast service. "They've got a great technology for what it is," says Mark Varel, T-Speed CEO. "We are a broadband provider. Our charge is breaking the bottlenecks and they're helping us do that."
One of the problems for service providers in fixed wireless has been line-of-site restriction, for which OFDM proponent NextNet, of Minneapolis, says it has the solution.
"These carriers are paying top dollar for spectrum," says Barbara Heine, NextNet marketing director. "Imagine if you could reach all customers, not just line of sight."
NextNet's technology will allow users to place the antennae on their desktop, and sidestep rooftop installations.
Typically, with fixed wireless, the customer's antennae need to be within sight of the tower at no more than 35 miles.
Thus, fixed wireless faces some of the same restrictions DSL and cable have - it's out there and it's darn good technology, but it's accessible only to segments of the population.
Other telecom heavyweights working with OFDM include AT&T [T], with its digital broadband service code-named Project Angel; Verizon Communications Inc. is working with Mountain View, Calif.-based Radix Technologies; Broadcom Corp. is using Cisco's VOFDM in select integrated circuits; and Philips and Luxembourg-based Tele2 SA announced products based on WOFDM.
While analysts dare not play favorites with spectrum technologies, they are keeping vigorous tabs on OFDM.
"This presents a much higher revenue opportunity for the service provider, all things being equal, of course," Kellett says. "It'll allow carriers to capture as many customers in a service area as possible."
wirelesstoday.com; |
