Industry eyes OFDM even as it deploys 3G services

By Sam Omatseye
RCR Wireless News, Volume 24; Number 1, January 3, 2005
(c) 2005 Crain Communications, Inc. All rights reserved.

Even as it begins serious deployments of third-generation technologies, the wireless industry is hedging its bets on next-generation technology.

Since W-CDMA and CDMA2000 someday may reach their tethers, some industry players are eyeing orthogonal frequency division multiplexing -OFDM-as the next big technology.

Major vendors say they have been working on it for years. ``We've been looking at it for up to 15 years,'' remarked Mikael Stromquist, executive vice president for strategy and marketing at L.M. Ericsson.

“It's a promising technology,” remarked Keith Nowak, spokesman for Nokia Corp. “We see it as one of the key technologies,'' beyond third-generation protocols.

Flarion Technologies Inc. often has been associated with the technology because its protocol, known as Flash-OFDM, played a large part in the past year in the possible future designs of Nextel Communications Inc. and German carrier T-Mobile International.

On the vendor side, Siemens AG has entered an agreement to support Flarion's technology, a move some industry players see as a big plus for Flash-OFDM. Motorola Inc. has partnered with Flarion to provide public-safety networks in the District of Columbia in a contract win where Flash-OFDM prevailed over CDMA.

But industry watchers say Flarion's offering is just a flavor of a complex bearer technology. Its product is still regarded as proprietary, although Flarion said it is working to make it interoperable. Qualcomm Inc., which has made enormous impact with its CDMA innovations, is also focusing some research and development resources on OFDM.

OFDM technology already is the bedrock of 802.11 and 802.16 technologies.
Always eager to lead in technology trials, NTT DoCoMo said it has successfully trialed what it calls a fourth-generation technology with radio-access equipment at 1 Gbps data rate in the downlink. The Japanese carrier said the 4G radio-access equipment employs variable-factor spread OFDM radio-access method and multiple-in, multiple-out (MIMO) multiplexing technique.

Prior to the anticipated merger between Sprint PCS and Nextel Communications, Flash-OFDM was expected to beat CDMA as Nextel's technology of choice, according to some industry watchers. Now the planned merger between the two carriers likely will result in combined CDMA networks for the parties since it is Sprint's technology of choice.
However, both Nextel and Sprint own 90 percent of the MMDS 2.5 GHz of spectrum, and many observers think that Flarion may win that portion for Sprint Nextel broadband services.

In Germany, there is talk that T-Mobile may use Flarion technology for its recently won license at 450 MHz.

Also in contention is IPWireless with its UMTS-TDD technology, which also has a strong OFDM strain.

Standards bodies Third Generation Partnership Project and 3GPP2 are trying to fashion a standard for the industry, but they are nowhere near settling on a standard yet.
However, OFDM already has some influence in existing networks. According to a source, the combined Sprint and Nextel network will end up having some OFDM components. IPWireless is holding trials in Japan and Asia, and some observers believe it will have its industry impact there.

But OFDM is still a data-only technology and converts its data to voice, explained Robert Sanchez, vice president and chief technology officer at inCode Telecom. As such, as it exists today it is not comparable to that of public switched telephone networks used everyday for telephony.

Still, OFDM allows end users to send data at Ethernet speeds and it is suitable for multi-carrier versions of WiMAX and multiple access versions of WiMAX that support data transfer, said Sanchez. He noted that OFDM allows carriers to assign bandwidth and towers to each channel, amounting to three times the speed of DO. This minimizes interference.

With cable operators eyeing wireless, Sanchez said Sprint Nextel could leverage the power of OFDM to remain competitive with new players.