LTE on the money

John C. Tanner
Wireless Asia

The LTE PR juggernaut is running on all cylinders, with several LTE networks already in commercial service (albeit on a limited basis), and more expected to go online before the end of this year. In fact, the 3GPP says that 22 operators will have launched LTE by year-end which is an eye-catching number, considering that this time last year, only three major operators NTT DoCoMo, Verizon Wireless and TeliaSonera had definite plans to launch LTE services before the end of 2010.

There is still plenty of skepticism about the business case for rolling out LTE that early, if only because of the paucity of devices. Voice-centric LTE handsets are still two years away, according to Ovum's consulting director for Asia Pacific, CW Cheung, making LTE a data-only proposition for those launching now. 

But the rollouts are happening now, and more and more trials are being announced. Perhaps more tellingly, the discussion around LTE is shifting away from technical capabilities and data speeds (which are currently within expectations, according to LSTI) towards the practical issues of deployment, and - more to the point - how much it's going to cost operators to roll it out. 

The answer will vary from cellco to cellco, of course, but one clear trend is that LTE raises some serious challenges to the old way of deploying cellular networks - i.e. macro cells with wide-area coverage. Even discounting the fact that most LTE networks will be running initially in the 2.6-GHz band, which means shorter ranges by default, LTE cells will be smaller than ever, putting a premium on cell capacity over coverage. That's already having an impact on base station design (and for the better, by most accounts) but it also potentially means a lot of extra deployment costs for cellcos - unless they deploy LTE in strategic islands. 
 
No more macros

The reason LTE requires smaller cells, says Dr Shahram G Niri, director of global LTE/SAE strategy and solutions for NEC Europe, is that the escalating growth of mobile data usage is emphasizing the need for maximizing capacity per cell, which in the 3G world means spectrum reuse. 

"Even today, 3G cells are down to a few hundred meters or even a hundred meters in some cases, when it was supposed to be kilometers," he told Wireless Asia. "That's because we're learned that of all the techniques we've come up with to increase capacity and the spectral efficiency, the biggest gains we're had was from reusing the frequency, which means we can reuse the same frequency everywhere, but that means smaller cells."

The same applies to LTE, even with the wider spectrum bands being allocated for it, he adds. "With LTE, the spectrum we have will not be enough to accommodate the growth of data traffic that we're seeing."

Bjorn Amundsen, VP and director head of mobile network coverage for Telenor, says his company has reached the same conclusion in its home country of Norway.

"Even just for 2G and 3G, in the inner circle of Oslo we have a base station every 50 to 100 meters today," he says. "Looking ahead two or three years to LTE, you'll need a base station probably in every building or every second building. That's going to be a huge cost."

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