Spectrum Issues Loom Large for Antennas

Although standards for 5G won't be finalized for some years, the industry can't wait, and it's forging ahead to develop pre-standards networks for deployment within the next two to three years.

But economies of scale apply to telecom networks and services in a significant way: there are potential sales of hundreds of millions of device and hundreds of thousands of base stations associated with rolling out a new wireless technology; component parts must be manufactured in volumes that mean they are cheap enough to support an investment case.

In the case of antennas and radio equipment, one important factor is that the number of different frequencies to which they are tuned must be kept as small as possible, for reasons of cost and space. You don't want to put more radios and antennas than absolutely necessary into any device or base station, and there is also a limit to the tuneable range of each radio/antenna system. The problem is that not only have 5G technical standards not been agreed upon yet, but neither have the frequencies that will be used.

Some pretty impressive research and development (R&D) work has been going on over the last few years to increase spectral efficiency and throughput, use beamforming and steering to serve more users per base station and show that very high frequencies can be used for cellular communication. However, because no one can be certain which frequencies might end up being used for 5G, building prototypes and testing them has required some degree of flexibility -- not least in the way that testbeds and instrumentation are used.

There is momentum building behind 3.5GHz and 28GHz frequency bands in several countries that are large enough for economies of scale to start to kick in, but the antenna development work has encompassed many more bands than this. Our compilation of trials and demos from the big vendors indicates at least nine different bands that are the subject of publicly announced work (and we suspect that other bands are being tried out in private research).

None of this research effort will be wasted as there is still much to learn about how best to form radio beams, steer them to where the user is, combine signals from multiple antennas, fabricate integrated radios/antennas and explore ways to overcome signal propagation challenges at high frequencies, for instance. But it is likely that vendors whose prototypes match the early 5G frequencies will have a head start in the market.

The latest Heavy Reading report, "Antenna Technology for 5G Networks," looks at the work being done to develop antennas to support the technical and performance specifications for 5G networks, showing how work done in LTE, LTE-Advanced and LTE-Advanced Pro has laid the groundwork. It examines multiple input, multiple output (MIMO) and massive MIMO, and their applicability and limitations and considers how antennas will be built to deal with the very high frequencies that many are proposing should be used in 5G networks. It explains issues of how best to form and steer radio beams so that they track users, and it summarizes the state of antenna R&D work by the big network equipment providers. Finally, the report profiles ten leading companies active in this field.

— Danny Dicks, Contributing Analyst, Heavy Reading

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