"In North America, it's less than 5% of backhaul on microwave today," said Michael Howard, principal and co-founder of Campbell, Calif.-based Infonetics Research. "That will change going forward over the next few years. North America will see a huge upswing in microwave use."
He estimated that 15% to 20% of U.S. mobile backhaul would be done over microwave in five years. Wireless carriers will not be alone in this trend: Global carriers have been using microwave technology much more broadly for years.
For them, leased lines have always been an extremely costly proposition. Now in the United States, the inability of copper lines to cover traffic needs means more expensive fiber or multiple T1 connections will be called for.
Howard said almost 60% of mobile backhaul in Europe, Asia, Africa and Central and Latin America is done over microwave. U.S. carriers have been slow to adopt the technology because leased lines have been relatively cheap. Foreign carriers were prompted to use microwave by the high prices or daunting green field deployment costs.
As mobile users become more and more data hungry, the copper lines that outfit many cell sites in the United States just won't cut it. The problem will become more pressing when Sprint brings WiMax and Verizon and AT&T bring Long Term Evolution (LTE) to market during the next five years.
With the first iPhone, for example, average data usage more than doubled, and now that applications are taking advantage of the faster connection to stream music, video and other data, bandwidth needs are sure to increase.
"Typically, the situation is you have leased lines, and if you can get additional leased lines at a competitive price, that is our competition," said Amir Zoufonoun, CEO of Exalt Communications Inc., a Campbell, Calif.-based microwave equipment manufacturer. "With WiMax and LTE, the model blows up. It's not scalable."
Zoufonoun said U.S. service providers already spend $8 billion a year on leased lines, and the operational expenses are just too great to continue adding T1 lines for each site.
Even before the 4G services hit, however, some service providers have found profitable uses for microwave backhaul, which often runs several times over the cost of its wired counterparts to deploy but can pay for itself in saved leasing costs.
Jordan Young, a network operations engineer for Texas service provider Partnership Broadband, said servicing many of his company's rural customers would be impossible using many traditional methods.
DSL, he said, was tricky because underground telephone lines were allowed to corrode and decay. Also, fiber providers were uninterested in deploying in the region because the low population density made the move unprofitable.
That left costly satellite options -- or beaming microwave from a central location to various sites, and then creating a small local wireless broadband network.
"Using wireless backhaul we're able to go in with a very low entry [cost] point," he said. "We're able to be very competitive."
And so far, Young said, the microwave spectrum has been very robust, requiring only a line of sight to have a strong signal between points in the network.
That might be some consolation to more traditional providers. Howard said that even aside from the cost aspect, the rate at which cell sites will need to be upgraded meant upgrading the underground infrastructure wholesale was impossible.
"When you're talking about 200,000 cell sites in North America, you just can't ... take fiber to all of those sites," he said. "Capital expenditures aside, labor aside, just timing wise, you can't do it."