Wimax struggles for its place in a post-3G world—again: just when you thought mobile Wimax had secured its role in the mobile broadband ecosystem as a complementary technology to 3G, the cellular camps have moved the goalposts with solid plans for post-3G technologies LTE and UMB. Telecom Asia re-evaluates mobile Wimax's business case

Telecom Asia, Nov, 2007 by John Tanner, Chris Everett

"If we stopped at HSPA, then sure, we'd fall off a cliff and mobile Wimax would have a market. But we're not," Ehrlich says.

In any case, the notion of rolling out Wimax ahead of LTE raises a valid question for cellcos: is Wimax a stopgap solution? And if it's not, what happens to the Wimax network once you've gone to LTE?

Alcatel-Lucent's Berkeley insists that there's no reason to look at Wimax and cellular as being mutually exclusive because there is a market for both static nomadic broadband and mobile broadband.

"It's not a question of one technology totally replacing another," he says. "If you build a Wimax network for static and nomadic services, you can change it to perform better by cutting off the mobility aspect and make it better as a static service. LTE is designed for high mobility, but Wimax can still serve a specific consumer segment, so there's no reason to scrap it. For example, Wimax can serve rural environments where LTE isn't likely to be rolled out for a long time anyway."

Transitional advantage

However, phased-deployment is one element of 3G that doesn't necessarily work against it. For both GSM and CDMA, backward compatibility is built-in, permitting service providers to selectively deploy the next generation of services into the market. Cellcos can start with LTE or UMB high-density urban areas and strategic indoor locations such as airports and business parks (much as they did with initial rollouts of HSPA and EV-DO Rev A or B, respectively) and let the previous generations handle national coverage.

Consequently, service continuity will be a key service differentiation between 3G and Wimax, says Riviora of Telecom Italia. "If you're moving and you can't get HSDA, you automatically drop down to 3G, or GPRS/ EDGE," she told Telecom Asia. "That's something guaranteed in mobile--no matter what, you will always have that data connection."

Another advantage is this: because LTE will be deployed in ITU recognized frequency bands, LTE will eventually have global roaming capabilities similar to current GSM/3G networks. And because the LTE handsets will be backward compatible with GSM and 3G, even at early stages of LTE deployment LTE subscribers will be able to roam throughout Asia.

Independent Wimax service providers will find that service limitations such as spotty coverage without a fallback capability to a lower-speed service and limited roaming capabilities could limit subscriber growth regardless how good or low-cost Wimax is.

All this is assuming, of course, that Wimax's real challenger will be LTE or UMB, rather than the HSPA or EV-DO Rev B networks already in service.

Qualcomm senior VP Jeff Belk has said for several years now that mobile Wimax doesn't hold a candle to any incarnation of EV-DO. GSMA's Ehrlich is equally bullish about HSPA, arguing that even today the mobile Wimax business case is on thin ice.

"When you look at how fast HSPA is roiling out now, and you look at markets like the UK, where you have five operators doing HSPA at 3.6 or 7.2 Mbps before you've even spent a dollar, and you've got to spend 2 billion pounds just to build your network and compete with them, any investor who's considering mobile Wimax has to ask themselves, where is their market? And what can they do differently or better than HSPA?" says Ehrlich. "As a businessman, I don't see an answer to that."