Alcatel-Lucent is preparing a CDMA base station that can be upgraded to ultra mobile broadband, filling in an important gap between the 3G and 4G equipment deployments. In doing so, Alcatel-Lucent said it was trying to overcome the biggest obstacle carriers will make during that transition: the need to deploy entirely new networks.

“Our intent is that we will reach a point where we can deploy a Rev. A base station with the RF assets that will support UMB,” said Mike Iandolo, president of Alcatel-Lucent's CDMA/EV-DO business. In fact, some of Alcatel-Lucent's evolution-data optimized deployments today already support those capabilities, he said.

The UMB standard has not been finalized — though the 3rd Generation Partnership Project 2 is expected to issue a final specification in April — but the basic shape of the technology has already been determined. UMB, formerly called EV-DO Revision C, will depart from CDMA using orthogonal frequency division duplexing (OFDM) on the downlink. That means a new modulation scheme over extremely wide channels compared to the 1.25 MHz carriers CDMA uses today, which in turn means new radios over new spectrum — the ingredients of a new network build (see story on page 38).

But Alcatel-Lucent's base station won't obviate that new network build entirely. While EV-DO can be upgraded to Rev. A with new software, any UMB rollout would require the rollout of an entirely new set of base stations, Iandolo said. The difference is that carriers wouldn't need to start from square one like carriers that are building completely incompatible networks, Iandolo said. The radio in the UMB base station would be different — as would the software and the antenna mast — but from the base station interface inwards, the elements would be common to Alcatel-Lucent's CDMA product line, making integration back into the CDMA network much simpler, Iandolo said.

Though it may not be the ideal upgrade path that CDMA 1X has offered to carriers for the greater part of the last decade, any promise of network continuity and reuse may help assuage concerns from CDMA operators, which watched their GSM counterparts spend billions of dollars more in universal mobile telecommunications system spectrum and equipment during the transition from 2.5G to 3G. The big fear of network disruption may cause CDMA carriers to look toward other technologies — a fear that became reality when Sprint chose WiMAX. Other carriers may make the same choice or opt to follow the GSM carrier's 4G technology of choice, long-term evolution (LTE). If CDMA/UMB vendors can show the time-to-market benefits of their technology and a definite continuity with their old equipment, they may be better able to persuade their customers to make the UMB leap, said Peter Jarich, analyst for Current Analysis.

“CDMA vendors are in a tough position,” Jarich said. “They know people are already turning away from CDMA. Now they have to explain why UMB is more compelling than LTE.”

THE THREE FLAVORS OF 4G

WiMAX:

A new technology based on the IEEE 802.16e standard, WiMAX technically is a first-generation technology, but Sprint's embrace of the standard pits it against other 4G technologies. WiMAX uses OFDM access on the uplink and downlink.

LTE:

Long-term evolution is the 3GPP's answer to the next-generation data network, using OFDM access on the downlink and single carrier frequency division multiple access on the uplink. GSM carriers are expected to choose LTE when they make they jump to 4G — unless they are tempted by WiMAX.

UMB:

Ultra mobile broadband is backed by the 3PP2 as the OFDM evolution path for CDMA networks. Though very similar to LTE, UMB supports a mixture of CDMA, quasi-orthogonal and non-orthogonal multiplexing for the uplink.