5G Wireless Technology: Cutting Through the Hype

Kelly Hill, RCR Wireless, November, 2017

Hype is certainly high for 5G, given that the industry is still technically in a pre-standard phase and that standalone 5G systems are still some time off.

5G is coming even faster than originally expected. In December, the first official specification from the Third Generation Partnership Project is expected to be released; 5G New Radio will finally make its standardized debut – although like Long Term Evolution, 5G will continue to evolve and be refined in the coming years.

“5G will not replace LTE,” Rysavy Research concluded in an August report for the GSMA. “In most deployments, the two technologies will be tightly integrated and co-exist through at least the late-2020s.”

Although the industry is preparing for 5G, LTE [4G] capabilities will continue to improve in LTE Advanced Pro through the rest of the decade,”  Rysavy wrote …. 5G will eventually play an important role, but it must be timed appropriately so that the jump in capability justifies the new investment.

KT, for example, plans to support two different frequencies from the get-go in its 5G network: 3.5 GHz as an anchor with better propagation, complemented by 28 GHz in dense areas. Given that networks are expected to initially be 4G/5G networks, testing will have to continue to support LTE alongside 5G.

Hurtarte of LitePoint noted that although “millimeter wave” tends to be treated as one category, there are significant differences between the components and frequency planning needed at 28 GHz versus 39 GHz. In addition, although some frequencies are widely agreed upon, there are other frequencies that may get the nod for 5G use: 24 GHz in China, possibly 40-43 Ghz and possibly even above 70 GHz.

There are some major challenges to the success of 5G, which are all interrelated: the move to mmwave, the need for ultra-density, and the question of when the economics of 5G will actually work well enough to take off.

Mmwave [millimeter wave] provides the huge bandwidths that are needed for fast speeds and high capacity, but the higher the frequency, the shorter its range and more susceptible it is to being easily blocked and reflected (thus the need for beamforming in order to focus the energy more tightly). Seasonal foliage, energy efficient glass windows with special coatings, and standard housing materials all present effective barriers to mmwave reaching indoors to customer premise equipment, operators and vendors have found in their field testing.

Denisowski pointed out that fixed wireless is one thing, but moving objects are another. Obstruction, not radiating sources of energy, is likely to be the main cause of interference in 5G systems: vehicles driving back and forth, or even wind farms can scatter microwave radiation.

Density of foliage “plays a big role,” said Thadasina of Samsung, which has been working with a number of carriers on 5G trials. “What we found is that for the mmwave signal, as it penetrated through trees, the thickness of the trees matters. Initially the impedence offered by foliage is linear, but beyond a certain density it is no longer linear … it kills the signal.” Building materials are well-known to play a role in transmission from outdoors to indoors, he added, but the angle of incidence does as well. The difference between 30 degrees to 60 degrees to 90 degrees can create additional impedance, Thadasina said, “some of those things make it challenging in terms of closing the link.” Moisture levels play a role as well, he said ….

Fiber is fuel for 5G, and its prevalence is increasing. SNL Kagan found earlier this year that global fiber residential investment increased sharply in 2016, and that fiber is on track to reach 1 billion subscribers by 2021. Meanwhile, in the U.S., Vertical Systems Group reported that 49.6% of multi-tenant and enterprise buildings had access to fiber last year, compared to only 10% in 2004.

Deloitte said earlier this year that it expects to see $130 billion-$150 billion in “deep fiber” investment in the U.S. over 5-7 years, due to a combination of broadband competition, ensuring 5G readiness, and expanding fiber into new areas.

Murphy of Nokia said that operators should expect that, depending on which frequency they deploy in, they will need 2.5 to 10 times as many sites as they have now. That’s a tall order, especially given that small cell sites in cellular frequencies can take 18 to 24 months to get site approvals – scaling small cells has been hard enough in LTE, with the market moving much more slowly than analysts had predicted or carriers would like.

“It’s going to take a long time,” Einbinder said. “Constructing a cell tower is hard. A micro-cell has a lot of the same issues”: power and fiber and access to a site, which a community may be reluctant to grant – California, for instance, recently rejected a measure passed at the state level that would have streamlined processes for small cells.

… Einbinder thinks that some communities will take initiative and want to be 5G economic centers. While that’s encouraging for operators, it may also mean that 5G coverage maps look very different from the familiar red, blue, yellow and magenta maps indicating nationwide coverage. “The resulting coverage maps might have a lot more to do with [communities] than any economic or technological drivers – it’s going to be driven by local preference.”

While early work estimated that as many as 40 to 50 homes could be covered by a single fixed wireless site, according to Rouault of EXFO, that number has turned out to be around five in testing because of the complexity of beamforming necessary to support multiple homes. “It’s not at the point we would say the verdict is out,” Rouault added. “The technology is proven to work, but to make the business case work, the scale is the problem right now.”

So the biggest question is where a breakthrough is going to happen that becomes the point at which 5G becomes a more attractive investment than LTE. “What can 5G do that other systems can’t? This is where there is no clear answer,” said Hemant Minocha, EVP for device and IoT at TEOCO. There is no 5G requirement for IoT [Internet of Things], he points out, and the business case hasn’t yet been proven out for ultra-low latency (not to  mention that LTE is capable of lower latency than it has achieved to this point in networks).

Key Takeaways:

• The industry is moving quickly toward 5G, with momentum in testing and trials. The first official 5G specification from 3GPP is expected in December, with a protocol-focused release coming in the spring of 2018.

• Many features and architectures in LTE, particularly gigabit LTE, will both underpin future 5G networks and provide lessons learned in making 5G systems work. These include dense fiber deployment, higher-order and massive MIMO, network slicing, virtualization, and mobile edge computing.

• The biggest challenge for 5G lies in a millimeter-wave based RAN, with significant challenges ahead for designing and deploying a workable, optimized and profitable mmwave network on a large scale.

The RCR Wireless report, “Transitioning to a 5G World,” can be downloaded at http://bit.ly/5Ghype.