Don Bishop 2017-10-04 01:05:04
Small cells have to be scalable to accept future 5G technologies so they don’t have to be installed all over again. With a variety of styles from which to choose, mobile network operators have an opportunity to select small cells that can be hidden or that can be installed in plain sight yet blend in with their environment. The demand for wireless communications bandwidth is increasing rapidly, something like 50 percent per year, according to Erik Lilieholm, technical sales manager for mobility network engineering at CommScope. “We’re trying to look ahead at the future technologies, talking to our key customers among the operators and trying to align our road map,” he said. “Despite the increasing demand for bandwidth, the average revenue per user for the operators is projected to remain flat,” Lilieholm said. “That drives the economy of deploying the small cells. We have to get to a cost of deployment that is lower than we had in the past.” A key part of obtaining such economy lies in standardizing small cell design and deployment, Lilieholm said. He said that standardization would allow manufacturers to produce small cells on a large scale at a reasonable cost. It would allow quick installation, preferably, Lilieholm said, with nonspecialized personnel and with minimum disruption to the installation site. “Robustness and reliability also are important,” Lilieholm said. “Small cells are distributed assets. They’re not like macro sites where you have a lot of equipment in one place. With small cells, you have equipment in many locations. Some locations won’t be accessible at all times. Thus, it’s essential that the small cell is reliable and doesn’t fail, and that it is robust and withstands attempts at vandalism. Those requirements put constraints on the design.” Efficiency Small cells have to be effective where they are placed, Lilieholm said, because the communications capacity they deliver is localized. He said the efficiency of a small cell site would be reduced by some percentage just by removing it 50 meters to 100 meters from its ideal location. “The need for efficiency also applies to antennas,” Lilieholm said. “Antenna performance is important, and it usually is proportional to antenna size. If you can accept a larger, more effective antenna, then you can get more capacity out of that one small cell.” Acknowledging that mobile network operators that deploy small cells want small devices, Lilieholm said that CommScope wants to reduce the equipment footprint. Some small cells use cabinets on the ground to house equipment, and Lilieholm said the cost of deployment and the time it takes affects how desirable it is to use ground cabinets. He said it is preferable to elevate the equipment, and an alternative is to centralize the equipment in a concept called C-RAN, which stands for centralized radio access network. Lilieholm said centralization offers some benefits for the performance of the network. “Small cells have to be scalable to accept the future 5G technologies so we don’t have to install them all over again,” Lilieholm said. “They have to be either visually appealing or visually inconspicuous. We talk about hiding these sites. But sometimes it is not possible, necessary or desirable to hide them. We can make them visually appealing. We can make them a part of the architectural landscape.” Photo 1 shows a small cell in a style known as Metro Cell that is a Pole Top equipment design. The radio equipment is housed directly below a canister antenna. Wraparound Cabinet Photos 2 and 3 show the wraparound cabinet in two other installations that use different antennas. The pole in Photo 2 has a traditional pole-top canister antenna. The pole in Photo 3 has stick antennas that are barely visible with the luminaire at the top of the pole. The stick antennas can be used along with other antennas on the same pole. Photo 4 shows a pole with stick antennas below panel antennas. With the pole in Photo 4, the radio equipment is housed in the base cabinet of the pole structure. Lilieholm showed other examples, such as an integrated pole (see Photo 5). “The integrated pole can be fully assembled in the factory,” he said. You can make all the cabling. Everything besides the radio installation, usually, is done at the plant. Then the whole thing is transported and erected on the site. That is one way we can improve the robustness and the quality of the product.” Mounting directly to a pole is a solution that is easy to install and flexible with respect the number of radios it can house. The enclosure shown in Photo 6 represents an attractive solution for concealed mid-pole mounting. It is designed to fit into the communications space between the two tiers of cabling on a wood pole. The antenna is not included in this one, but it is likely to be mounted on the pole. “It’s essential that the small cell is reliable and doesn’t fail, and that it is robust and withstands attempts at vandalism. Those requirements put constraints on the design." — Erik Lilieholm Standardized Enclosure Photo 7 shows a fiberglass enclosure that’s been standardized by New York City. Lilieholm said it’s available in a number of colors. “It’s aesthetically pleasing, once it’s mounted on a pole,” he said. “It can contain DAS equipment or, as shown here, some small cell radios.” Some higher-capacity installations fall within CommScope’s definition of small cells. A combination equipment and antenna enclosure with a radome can be made with fiberglass for a hard radome or with fabric for a soft radome. Lilieholm said it fits larger antennas, so it will be more effective. Photo 8 shows the combination enclosure installed on a rooftop. CommScope classification uses another classification, the mini-macro site or the mid-cell site (see Photos 9 and 10.) Because it’s a tall structure mounted on top of a pole in this case, it works more like a macro. The cylinder can be placed on the ground for a site that’s 35 to 50 feet tall. “It can have sectorized antennas and longer antennas, which means you get more power out of it, and you can have a large number of radios and multitenants, so you can have two or three operators on that same tower,” Lilieholm said. “Because you get better coverage from this type of site, you might be able to replace four or five small cells. And because you have multiple operators, you can multiply that. So, one of these installations, although it is difficult to hide, can eliminate a number of small cells. This works in some scenarios but not all. It’s something we think will be interesting to centralize the coverage.” Integrated Pole Photo 11 shows an architecturally integrated pole with a luminaire. Lilieholm said there’s some opportunity to customize such poles, but because each is carefully engineered and assembled with attention to thermal structural aspects, there are limits to how much they can be modified for specific applications. Even with all the attention paid to small cells, Lilieholm said there are more factors to consider. “It’s about the access, and it’s about the data centers at the back end,” he said. Erik Lilieholm spoke at this year’s AGL Local Summit in Seattle. For information about AGL Local Summits, visit www.aglmediagroup.com.
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