Backhaul key as small cells enhance LTE performance, increase network complexity

Where available, fiber is the ideal backhaul transport platform, because it can provide high throughput rates and low latency. However, the cost of laying fiber—primarily associated with the cost of burying fiber underground—makes it economically impractical to deploy it as a backhaul solution to all small cells, according to Amit Khetawat, director of products for AOptix.

“I think the need for fiber is something we all recognize,” Khetawat said. “But fiber is not going to be ubiquitous. There will be a set of situations where fiber just cannot be trenched, so you won’t have fiber. Or, there are conditions where carriers would want to minimize their opex costs by not leasing from the competitive fiber out there.

“In those conditions, you need a highly scalable wireless alternative. AOptix offers that.”

AOptix does this by leveraging composite optical-RF (COR) technology, which combines free-space optics with millimeter-wave RF technology to deliver a high-throughput backhaul link that will not be cut by a backhoe and is able to work in weather condition—like heavy rain—that has troubled legacy wireless-backhaul solutions.

The result is that this AOptix solution—developed originally for the military—can deliver “fiber-equaling performance, basically,” Khetawat said. “It’s a virtual fiber, without requiring someone to lay out the physical fiber. We can certainly meet the characteristics of fiber, if not better. The reason I say, ‘If not better’ is that we use free-space optics, and light that travels through air is slightly faster than light that travels though a fiberglass medium.

“So, from a latency perspective, we can certainly meet those challenges. In terms of capacity, our product offers 2 GB/s, and it scales all the way up to 10 GB/s, so we certainly anticipate the demand for future needs and can meet those.”

In addition, the AOptix solution can be deployed quickly, because it does not require trenching or time-consuming FCC applications to use the high-frequency spectrum (see video for more details on this), Khetawat said. Setup time is minimized by using a tablet-based application to direct the backhaul beam in the correct direction and automated tracking technology that helps ensure that the link remains in place, even if the antennas at either end of the link are moved slightly by the wind or other force.

“It basically fully automates the process,” Khetawat said. “All they have to do it mount it on a physical pole, hoist it up and the two ends of equipment automatically find each other within minutes. We’ve completely made it idiot-proof, so to speak.”

“In terms of maintenance, you want a network that, [after] you build it, you can forget it. You don’t want to roll a lot of [maintenance] trucks because someone says, ‘Oh, my microwave [antenna] moved.’ You don’t want those kinds of issues. What we have is a technology called active beam steering, so that once you’ve aligned [the antennas properly], it automatically tracks. So, even if the tower moves or twists, the far end will be able to detect it and move with the tower. That minimizes the need for rolling out trucks.”