CommScope and Nokia have solved for an antenna problem that they anticipate as carriers upgrade to 5G New Radio (NR), using both low-band and mid-band spectrum.
“The problem is that operators want to add capacity at 3.5 GHz, but they don’t have room,” said Martin Zimmerman, an engineering fellow at CommScope. When he says, “they don’t have room,” he’s referring to a lack of physical space on towers to deploy additional massive MIMO antennas.
He said, “The problem is that you’re not starting with a blank slate. You’ve got existing equipment on towers.” These towers sometimes can’t structurally handle more weight. Also, a lot of times operators don’t own the towers, but instead they lease them. And the leasing fees often depend on the number of products they have mounted on the towers as well as the square footage of the faces of the products deployed on the site.
CommScope and Nokia have teamed up to develop a new interleaved passive-active antenna (IPAA) radio platform. CommScope brings its antenna expertise, and Nokia provides the radios. Operators can replace their current passive antennas on towers with the new IPAA 5G NR equipment that includes both passive and passive-active antennas.
The hybrid solution consists of two modules:
· A purely passive module that supports multiple bands in the range from 700 MHz to 2.7 GHz.
· A passive-active module that includes TDD beamforming functionality for 5G n78 (3.4-3.8 GHz). This passive-active module also includes an extension of the low band arrays to avoid re-optimizing existing networks at 700-900 MHz.
These modules are “interleaved” in the same enclosure.
“What we’ve done with this IPAA is we’ve figured out how to integrate this extra equipment into the same footprint as the existing footprint,” said Zimmerman. “It looks like one antenna when it’s all put together; one antenna that’s two pieces that’s the same size as the antenna you started with.”
Europe vs. U.S.
He said there’s already some demand for IPAA in Europe. In the United States, they’ll become important when carriers have secured C-Band mid-band spectrum and want to start deploying antennas for it. He said at wireless operators, the top technologists come up with a spectrum plan and a 5G plan based on capacity, but it’s the local RF engineers who have to make it all happen.
“If you’re an RF planner in a city, your sites may not allow you to put another antenna,” said Zimmerman. “The actual people in charge of implementing it have to deal with real estate, leasing and structural. The reality is that assumptions made at headquarters don’t always apply. A lot of sites can’t add another antenna.”
“Integration of active and passive antennas will be a major challenge for the industry over the next five years,” said Joe Madden, chief analyst for Mobile Experts, in a statement. “The laws of physics can create some difficulties in making integrated antennas small and lightweight…but operators will need the integration to add capacity on their crowded towers. We expect clever engineering to create opportunities for the most innovative antenna suppliers.”
CommScope and Nokia have already received some orders for their IPAA in Europe, and they’re doing trials with other customers. These operators are ahead on 3.5 GHz spectrum, because their countries held auctions before the United States. “In the U.S., the equivalent would be the C-Band auction which takes place next month,” said Zimmerman.
Asked if CommScope and Nokia can customize the IPAA platform for different frequency bands, Zimmerman said, “Yes. We can customize both the lower and upper section for whichever frequency band a customer wants. Radios tend to be the same, but antennas vary. We see a lot of different bands and need different port combinations.”