How does it work?

At the heart of the new technology is the lightRadio cube, which includes an innovative diplexer, radio, amplifier, and passive cooling in a small cube that fits in the palm of the hand. The size of each cube varies, based on the frequency band being used, with a cube for the 2.6 GHz band measuring 2.5 by 2.5 inches, while a 700 MHz cube would be 6 by 6 inches, “because you can’t get away from physics,” Gruba said.

“What you do with it is you make these like Legos and put eight or 10 of them in a column, and that becomes your antenna with your amplifier,” he said. “Each one of those amplifiers would have somewhere between 1 and 5 watts. So, if you had eight of them stacked in a vertical column, then at 2.6 GHz, you would have 40 watts of power.

“Here’s the key: If you lost one of these elements because it goes bad, you still have 35 watts of power that you’re transmitting — you’re still serving customers. And, when the weather’s nice … you can do a field replacement of that unit.”

Housing the amplifier in the antenna unit increases efficiency, said Ken Rehbehm, a principal analyst with Yankee Group.
“You basically have an integrated unit, with no power loss on a feeder going [between the amplifier and] the antenna,” Rehbehm said.

In addition, the lightRadio antennas are able to support 2G, 3G and 4G technologies in a single structure, which allows the unit to be much more discreet than traditional cellular antennas. By locating these antennas on light posts, signs and the sides of buildings, carriers hope it will help them survive the always-challenging gauntlet of zoning and municipal approvals as they seek to add sites to serve high-capacity areas.

“The key is that I can stack two columns side by side, and now I’ve got two antennas. I can operate at 2.1 and 2.6 GHz,” Gruba said. “In the same housing, I can put a passive antenna for a lower frequency — 900, 800, maybe even 700 — in one package. Now, I have three of those stacks of antennas that could be down into one. So, that’s cheaper and the city planners are happier.”

Of course, baseband processing and LTE base stations still are required, but the new Alcatel-Lucent approach allows housing this functionality at the base station at the bottom of a tower or building. These components can be housed in hubs — often called “hotels” — that would serve 25 to 30 sites in a geographic area in a “cloud” computing architecture.

This approach should help operators deal with a longstanding frustration regarding inefficient use of baseband processing resources. In the traditional architecture, baseband resources have to be distributed at base stations in anticipation of peak traffic loads, but those processors use only a fraction of their capacity during off-peak hours — think about Wall Street at night or an area around a baseball stadium at sunrise.

By consolidating the baseband processing in a “hotel” designed to serve numerous sites, the processing function can be done more efficiently, providing the same — possibly better — processing capability for less money.

“If you take that to the logical extreme, it’s a powerful tool to consolidate baseband processing and be able to apply it to portions of the network where you need it,” Rehbehn said. “It’s not fixed out at the sites and dedicated to a site that may or may not be a heavy loaded site. As a traffic load changes in a network, it stands to be an excellent way to optimize a key resource.”

In addition, centralized processing also enables coordinated delivery of packets to a user at the edge of multiple cells, which has resulted historically in interference issues as each cell site independently tries to deliver data to the user.

“Instead of doing what I was doing before, which was creating interference, I can now use that in a positive way and deliver bits to the user harmoniously across several sites,” Gruba said. “Instead of being independent and acting autonomously, now I’m coordinating between them.