WIMAX: The Long Goodbye

Ahead of the LTE North America conference in Dallas on the 8-9 November, at which he will be a keynote speaker, speaks to Stephen Bye, CTO of US carrier Sprint Nextel.

As the world transitions away from 3G to next generation mobile services, the US market in particular is in a state of flux. MetroPCS and market leader Verizon have launched LTE and AT&T is due to follow suit imminently; and if regulators allow, AT&T will next year swallow Deutsche Telekom’s US play, T-Mobile.

Big changes are also afoot for third-place mobile player Sprint. The company drew the first ‘4G’ blood when, in late 2008 and in conjunction with partner Clearwire, it launched a WiMAX network across the US. However, it is LTE that has come to dominate the next generation mobile network landscape over the last couple of years, and it’s an open secret that Sprint will soon be making a move towards LTE.

When spoke to Stephen Bye, chief technology office of Sprint, that move had yet to be made official. What the firm has been talking about is its Network Vision program, a comprehensive network upgrade strategy that, as Bye says, will enable it to, “very easily upgrade and support whatever’s coming down the pipeline”.

If any operator is experienced enough to take on the challenges of a new technology it is Sprint, which as Bye wryly puts it, supports “an interesting mix of different technologies”. This is a reference to the fact that as well as the WIMAX at 2.5GHz, it also runs a CDMA EVDO 3G network at 1900MHZ as well as, uniquely, an iDen network, operating at 800MHz.

Operating all these technologies together makes for a large, bulky and relatively inefficient macro  base station set-up, something the firm’s Network Vision upgrade is intended to address, by moving to one-cabinet, multi-mode units.

“We’re putting into place basestations that allow us to use different RF technologies on different frequency bands,” Bye explains. “So for instance on one side we can have a combination of CDMA, LTE or WIMAX across different radio bearers, be it 800, be it 1.9, on all the frequency bands that we have support for. We’re well on the way to deploying Network Vision, which gives us the flexibility to carry a lot of traffic over different bands on the basestations on the core network”.

While Bye isn’t able to nail Sprint’s colours to the LTE mast just yet, he says that the network refresh will give Sprint, “the opportunity to upgrade to whatever technology we decide to adopt going forward—at a much lower cost. It future proofs our business and it also gives us the flexibility to take advantage of other spectrum, as and when that comes to market”.

Bye also says that, as well as enabling it to keep up with next generation mobile technology, Network Vision will also be of great benefit to those replying on the older 3G CDMA network. “There are things that we’re doing to substantially improve the coverage and capacity on that network. Because what you can buy today in terms of technology is far superior to what we were deploying five or ten years ago. The one thing that we will see is much better coverage and much better quality.”

At the time Sprint was hoping that its early move into WiMAX would enable it to build up an unassailable lead in 4G. Of course it didn’t work out that way and Verizon’s relatively early move into LTE has, to a large extend headed it off at the pass. But has that speculative WiMAX play given Sprint any first mover advantage at all?

“There’s a benefit to that experience to having been in the market earlier, and the experience of building and managing capacity in that network is not lost us as we go forward,” he says. “How do you engineer the network? How do you optimise the network? How do you tune the protocols to maximise performance? That absolutely gives us a competitive advantage. And that’s really the benefit of having time to market.”

It can also be argued that, on a technical level, there are a lot of similarities between LTE and WiMAX, as Bye points out. “That knowledge that we have developed over WiMAX is easily transferable and extendable to any other OFDM technology, because WiMAX is OFDM – LTE is no different from WIMAX in that respect. The structure of the MAC layer and the uplink is different but there’s a lot of learning about our technology that is easily transferred over.”

Bye also offers up some thoughts on the FDD vs TDD debate running in the industry and believes that it’s not an either-or scenario. In fact, he points out that the selection of one over the other is actually unlikely to be a technology decision.

“The spectrum allocation will determine which of those solutions you end up deploying. If the licences are granted in paired blocks, then FDD is really only the feasible solution you can use. You can argue the merits of one technology over the other, but it really comes down to the licensing and the band structure that will determine how much TDD and what FDD you use, and how do you maximise the available spectrum that you have. So it’s likely that you’ll end up with a combination of the two.”

The only real downside, he says, is that having to support both will inevitably push up the complexity, and therefore cost, of end-user devices. That said, he believes this to be a price worth paying in order to solve the data challenges all carriers are facing.

“If we can at least get to a common baseband technology, then I think there will be economies of scale that will be afforded by that”.

Bye also reveals that Sprint will be using small cells to ensure that it deals adequately with capacity issues which, like all carriers in the industry, is a challenge that Sprint is facing. In fact it’s been a victim of its own success according to Bye. “Of all the carriers in America, we probably have the highest penetration of smartphones and of 4G devices—we are seeing tremendous consumption on those”.

It certainly not an issue that’s going to go away, especially if Sprint is looking to continue to stand alone in offering an unlimited data package, as it currently does for its WiMAX customers—something of which Bye is evidently proud. “We have an unlimited data plan and we are the only carrier in North America that continues to have one. And of course that is good for our customers. Most carriers in North America have chosen to go for tiered data offerings and that just makes it complex for customers. But we’ve stayed with a simple unlimited offer.”

One topic that draws no response from Bye is Sprint’s deal with LightSquared. As part of the proposal, LightSquared would pay Sprint a total of $20bn towards the build out of an LTE network, and Sprint would then lease those towers back from LightSquared as a customer. According to reports, LightSquared owner Philip Falcone has already written to its investors informing them of the deal, but with the would-be wholesale LTE operator currently mired in regulatory troubles over its GPS interference issues, Bye declines to comment.

But he is happy to reiterate Sprint’s robust views on the proposed AT&T and T-Mobile USA merger. “We actually think it’s bad for customers,” he said. “We think that the deal is basically an opportunity for AT&T to consolidate and remove a viable competitor from the market. We think customers will be the losers in that and we think the industry will suffer for that consolidation, given the market structure post that kid of merger. That being said, what with being the 3rd largest in the US with or without that deal, we still have 50m+ customers. We just think that that proposed merger is no good for consumers and not good for the industry. We are very public in our opposition to that deal.”

For the time being, though, Sprint has enough consolidation issues of its own to focus on. It is widely accepted that the firm’s mix of network technologies is unsustainable and the firm’s future will look a lot brighter once it has embarked on the next stage of its technological evolution.

The LTE North America 2011 conference takes place on the 8-9 November 2011 in Dallas, Texas.

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