RCR Wireless: Densified 4G/5G News

From the RCR Wireless News Digital Network


The following text is selected from an RCR Wireless Editorial Report: Transitioning to a 5G World; By Kelly Hill on November 8, 2017

This report and others from RCR Wireless are available for download here.

  • Wireless in the enterprise. A deeper reach, a more active role for venue owners; By Monica Paolini on November 13, 2017
  • Editorial Report: Wireless and Wireline Convergence; By Sean Kinney on October 25, 2017
  • Enterprise IoT Report: The building blocks of smart cities – IoT policies and technologies for urban sustainability; By Enterprise IoT Insights on August 30, 2017
  • Feature Report: Testing and Analyzing Spectrum Interference; By Kelly Hill on August 16, 2017
  • Feature Report: Ultra high speed fixed broadband: The first phase of 5G; By Sean Kinney, Managing Editor on July 19, 2017
  • Analyst Angle Report: Mastering analytics. How to benefit from big data and network complexity; By Monica Paolini on June 28, 2017
  • Enterprise IoT Report: Embedded IoT design – The basics; By Martha DeGrasse on June 21, 2017
  • Feature Report: Enterprise DAS, small cells and signal boosters: indoor densification trends and strategies; By Sean Kinney, Managing Editor on June 7, 2017
  • Analyst Report: Advances in IIoT Made Possible by Innovations in 5G, Virtualization and the Cloud; By RCR Wireless News on May 31, 2017
  • Editorial Report: Leveraging Unlicensed Networks and Services; By Kelly Hill on May 17, 2017
  • Editorial Report: FTTx: C-RAN, Fronthaul and Remote Radio Heads; By Martha DeGrasse on April 12, 2017
  • Editorial Report: Public Safety LTE; By Kelly Hill on March 22, 2017
  • Feature Report: Smart City Use Cases and Trends
    By RCR Wireless News on March 22, 2017
  • Feature Report: Opensource – virtualization platforms, standards, deployments, RTC; By Dan Meyer on January 18, 2017
  • Feature Report: Connected Car connectivity and services – is the industry ready?; By Kelly Hill on December 7, 2016
  • Feature Report: Securing mobility and cloud in the age of analytics; By Dan Meyer on November 9, 2016

5G Snapshots from Oct/Nov 2017

A. Key takeaways from “Transitioning to a 5G World”

  • 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 network, with significant challenges ahead for designing and deploying a workable, optimized and profitable mmwave network on a large scale.
  • 5G will have to prove itself in order to earn investment: some operators are saying, ‘How can we get more out of 4G and delay 5G, because it’s going to be really complex in the high bands?'”

B. Recent 5G Testing and Deployment News

Nearly every day, it seems that another company announces a new “5G” test, trial or product. Here is a snapshot of recent 5G-related testing announcements during the month of October.

  • Verizon is working on massive MIMO with Ericsson. In a test in Irvine, Calif, the two companies used a 20 megahertz channel of AWS spectrum (2100 MHz) to support 16 radios connected to an array of 96 antennas.
  • Multiple T-Mobile US executives have said that as the carrier begins to roll out its newly acquired 600 MHz holdings, that the radios will be software-upgradable to 5G.
  • KT recently re-confirmed that it expects to launch commercial 5G services in 2019, with a pilot network to be available at the 2018 Olympic games in PyeongChang. KT has already signed an infrastructure access agreement with Korea Expressway Corp. for access to major roads and facilities in PyeongChang, and plans to launch the trial service network in February 2018 with five months of testing prior to launch.
  • South Korean operator LG U+ worked with Huawei on a field test on 4G/5G dual-connectivity, which linked a 3.5 GHz base station with a 28 GHz base station to achieve a downlink rate of about 20 Gbps. The tests took place at an LG U+ 5G testbed in Seoul.
  • The Chinese government has confirmed its plans to complete its second phase of 5G testing by the end of this year and expects to have prototype products by June 2018. Five companies, including Huawei and ZTE, have built 15 stations for 5G testing in Huairou District in Beijing.
  • ZTE and French telecom group Orange announced a partnership to jointly work on 5G use case development, including testing a 5G core network, standalone architecture, end-to-end network slicing and 5G overlay architectures. ZTE plans to build a 5G innovation and research center in L’Aquila, Italy.
  • Nokia has signed an agreement with Russian operator Rostelecom to set up a 5G pilot project zone in the Skolkovo Innovation Center tech area near Moscow.

C. The Fiber-Optic Predicament

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.

Telecom operators have made fiber investments a major focus:

  • Verizon, spent much of 2017 boosting its fiber access as part of its One Fiber initiative. The carrier put $1.8 billion into acquiring XO Communications’ fiber assets, then followed up with fiber supply deals with Corning ($1.05 billion over three years) and Prysmian ($300 million over three years).
  • CenturyLink recently closed on its $34 billion acquisition of Level 3, which will increase CenturyLink’s fiber network by approximately 200,000 route miles.
  • In Europe, Vodafone plans to invest $2.39 billion over the next few years in boosting gigabit-capable infrastructure, including fiber and upgrades to its cable network.

Thomas Neubauer, VP of business development and innovation at TEOCO, said that fiber is one of several areas of investments that service providers are making with 5G in mind, as a direct challenge to the cable industry’s fixed wireless access. “That’s going to happen, no question about it,” he said. “That is a business case that will work out for them and will soon become a billion-dollar business.”

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.

While all that spending sounds encouraging, there are a number of practical issues that will make fiber deployment challenging and underscore the need for careful consideration of emerging network architectures, according to Yvon Rouault, technology advisor in the office of the CTO at test company EXFO — particularly as network speeds increase.

“Transporting more than 10 Gbps on the fiber . . . is not easy on very long distances,” he said, due to phenomena such as dispersion and phase modulation which significantly impact the bit-error rate. To account for that, Rouault said, “very probably, we’ll see an explosion of mini-data centers, or maybe virtual machines running very close to the antenna site for some specific use cases.”

“Backhaul is not ready for 100 Gbps, but they will need it,” Rouault said, while front haul is moving to 10 Gbps and will eventually need to be faster as well, in order to support expected 5G latency demands — which will pose issues if front haul needs to be more than 10 km in distance. “People are totally underestimating this. We’re preaching this right now to operators, to convince some of them not only to accept it but to understand it.”

Transitioning to a 5G world

This report looks at how the transition from LTE to 5G is shaping up; the major technology approaches that will migrate and shift from 4G to 5G; and how test equipment and approaches have to change in order to support 5G, from the chipset and device to the air interface, network architectures and network software.

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.

Of importance, many features considered “5G” technology are being applied to 4G/LTE even as they are being debated in 3GPP.

5G trends and expectations

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. But the level of interest, and many of the results of ongoing tests and trials, are promising. Ericsson’s second annual 5G Readiness survey of operators found that 78% of respondents were involved in 5G trials in 2017, compared to 32% last year – and 28% of respondents expect to deploy 5G in 2018.

“The industry is moving faster than maybe we thought we’d be able to,” said Saul Einbinder, VP of venture development for Spirent Communications. “3GPP is basically pulling out every stop they can think of to get the [non-standalone] spec ready by the end of this year.” 5G, he added, “feels a little bit more real.”

Analysts have rosy expectations.

  • TechNavio has forecast that the global 5G equipment market will see “tremendous growth and will post a staggering [compound annual growth rate] of more than 32%” until 2020.
  • Accenture has estimated that the economic impacts of 5G could be up to $500 billion in Gross Domestic Product growth, including 850,000 direct jobs over seven years of build-out and another 2.2 million indirect jobs across communities.
  • SNS Research estimates that for the fixed wireless access use case being explored by carriers including Verizon and AT&T, “5G-based FWA subscriptions are expected to account for $1 billion in service revenue by the end of 2019 alone” and grow at a CAGR of 84% between 2019-2025.

Gearing up for transition

Despite all that hype, 5G isn’t going to spring into ubiquity overnight. The move to 5G is a long-term transition, not the flip of a switch. Much like 2G networks still exist alongside 3G and 4G networks, 4G Long Term Evolution is expected to be just that: long term.

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.

Many of the capabilities that will make 5G so effective are appearing in advanced forms of LTE. As Mike Murphy, CTO of North America for Nokia, puts it, there is a general theme that “a main idea starts in 4G and is institutionalized in 5G.”

Some of those “main ideas” include:

A. Radio Access Network technologies including carrier aggregation and higher-order/ massive MIMO. What started with two-component-carrier CA, with 20 MHz channels, is evolving to three, four and five component carriers in LTE. Adnan Khan, senior business development manager for wireless products at Anritsu, said that some carriers are even exploring going beyond official specifications to look at six component carriers.

In 5G, the channel widths become dramatically wider but the general idea remains the same. Gigabit LTE is often being achieved with the integration of unlicensed frequencies. Likewise, relatively simply 2×2, 4×4 and 8×8 MIMO in LTE scales up in 5G to massive MIMO implementations. MIMO represents a 50% to 5x increase in network capacity, depending on whether it is deployed in an FDD or TDD context, according to Paul Challoner of Ericsson, speaking at the recent Competitive Carriers Association conference.

Luke Ibbetson, chief engineer for group research and development at Vodafone, said that the operators are exploring massive MIMO “with a view toward 5G, but it’s being lightly applied back into 4G as well. We’re able to start to get some early and very real-world experience of how well massive MIMO works before we get to 5G, because we can see how well it works when it applies to LTE. We’re already starting to get a much more calibrated view of what . . . massive MIMO can bring.”

B. A focus on a software-centric, automated, virtualized network. The virtualization of the network is well underway, with or without 5G. But the flexibility and automation of 5G essentially assumes a software-defined, virtualized network, said Nokia’s Murphy.

“Virtualization,” Ibbetson said, “is happening anyway. It doesn’t have to be heavily coupled with 5G.” Automation is going to be key, he added, but it has many components: SON, SDN, orchestration and analytics, as well as mobile edge computing, all of which are being implemented in LTE.

Network slicing” in 5G aims to fulfill the promise that granular “quality of service” was supposed to achieve in LTE, but which has ended up being largely limited to prioritizing voice over LTE traffic.

C. Access architecture changes, including fiber proliferation and mobile edge computing. As Viavi has talked to its largest operator customers, Yamany said, they are thinking about network splits and architectures for 5G within an LTE Advanced Pro context.

“They understand that 5G or no 5G, how you want to do the densification of some areas of the network to include virtualization as well as maximizing bandwidth at the same time – you’re going to have to do the split anyhow. 5G or no 5G, the split is happening,” Yamany said. “I can tell you that right now, most of the focus, if you talk about the physical network design, is in time synchronization,” Yamany added.

When functions are being moved from where they have typically resided in the network, to another place, whether there is aggregation or disaggregation involved, the synchronization is key to proper functionality. “If you don’t do it right, it will destroy the latency of your application,” he said.

Forward-looking operators have already started assessing the qualifications of their circuits to see if they can support 5G-level latency. Right now the focus is not necessarily on reaching 1 millisecond latencies, but coming close – 2-3 milliseconds as a target. Nokia recently demonstrated 2 millisecond latency between a base station and a handset in an LTE context, with SK Telecom.

With all of those areas yet to be fully realized in LTE, it’s no wonder that in some regions network investments are still focused on 4G. Even in the U.S., where AT&T is proceeding with 5G mmwave fixed wireless trials, the carrier earlier this year labeled its project to bring LTE Advanced Pro features to 20 cities by the end of the year as “5G Evolution”.

Ibbetson of Vodafone said that LTE gives the carrier a chance to see how close to 5G it can get with 4G in the context of mobile edge computing and low latency, for instance. “We’ve had a very good experience in LTE in terms of it being much more capable than 3G ever was.”

Although the industry is preparing for 5G, LTE capabilities will continue to improve in LTE Advanced Pro through the rest of the decade,” Rysavy wrote. “Many of these enhancements will come through incremental network investments. Given the scope of global wireless infrastructure, measured in hundreds of billions of dollars, offering users the most affordable service requires operators to leverage investments they have already made. 5G will eventually play an important role, but it must be timed appropriately so that the jump in capability justifies the new investment.”

5G test evolution

5G is a 10x increase in frequency and a 10x increase in bandwidth,” pointed out Jeorge Hurtarte, product manager at test company LitePoint. “So test equipment needs to be made available to support not only the frequency, but the bandwidth” – up to 2 GHz of bandwidth.

Hank Kafka, VP for analytics and access architecture for AT&T, pointed out that the jumps from 2G to 3G to 4G revolved largely around working in similar, sub-6 GHz bands and adding new features to improve efficiency and speed. 5G, he said, is a much larger generational leap because it involves both new technology and new bands at millimeter wave frequencies.

Kafka said that AT&T has explored a number of potential frequency bands in the lab, from sub-6 GHz all the way up to 73 GHz. Beyond its commercial trials, the carrier has focused its testing efforts on filling gaps in knowledge about the mmwave spectrum environment. e said that thus far, that test system has yielded information about the effect of rain and weather as well as insights about propagation in relation to different types of trees, all of which will be important as 5G networks evolve into planning phases.

Kafka sees four specific challenges for test in a 5g context:

  1. supporting high frequencies with 1-2 GHz bandwidth;
  2. Supporting radiated, OTA testing for devices which cannot support cabled test;
  3. The need to test multi-antenna arrays; and
  4. The need for enclosed OTA testing for beamforming.

Kafka noted that while the military has a long history of using mmwave frequencies, “it is definitely a recent phenomenon” for commercial wireless operators.

Another firm, LitePoint, has test solutions at both 28 and 39 GHz, two of the bands most widely expected to support 5G NR. In order to conduct OTA testing, Litepoint utilizes a horn antenna that captures the energy coming from the device under test from a range of 60 centimeters or so, he said, in order to work in the far field to see if each antenna is working at the specific power level and phase that it is supposed to.

Many features from LTE will carry over into 5G tests

Those features include:

A. Support for many bands. John Smee, VP of engineering for Qualcomm Technologies, said that the LTE expansion of band support to dozens of bands would likely surprise the tech community of a decade ago, when a tri-band phone was considered a “world phone”. 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.

B. Test automation and modular equipment. In previous generations, testing often relied on tests that had to be walked through one-by-one, with many manual adjustments and rotations. “Now, it’s automated test cycling through a huge number of combinations,” Smee said, particularly when it comes to over-the-air testing in a millimeter wave context, with beamforming and beam-tracking. “That’s something that’s being taken to the next level [in 5G],” he said. This decreases the amount of time spent on 5G testing, which is a big concern given the enormous increase in the number of scenarios that could be tested, versus the bare minimum that must be tested to ensure quality.

Given the large number of antennas envisioned . . . things can get out of hand pretty quickly,” he said. “You can’t haul in a dozen channel emulators – whereas in a 4G context, maybe you had one or two. It doesn’t scale to support that.”

C. Flexibility and efficiency. Smee of Qualcomm said that while the chipset company is keenly focused on initial 5G support for the features of the standard that are of most interest to operators, 5G will evolve in much the same way that LTE has. “Over time, as the firmware is updated at the base station and … as the standard marches forward, you more fully exercise the numbers of scenarios and configurations,” he added. “So one of the important things is … exercising a relatively full subset of the standard such that to ensure that the devices will be deployed for a long time and be successful, even as the deployment evolves and new configurations and more dynamic operation comes into play.

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. The next World Radio Conference, which weighs in on the use of global frequency bands, isn’t until late 2019.

Out of the lab and into deployment

With mmwave 5G systems expected to start deployment in 2019, the testing focus is rapidly shifting from one of early trials based on prototypes, to the question of what changes will be necessary for largescale manufacturing, network planning and network deployment. Those tools, in many cases, are still in very early stages or don’t yet exist – or they’ll need to be simplified so that production workers and field techs can operate them with minimal training.

In a manufacturing environment, several factors in particular stand out for 5G test needs: lower costs, faster testing capabilities, and the ability to be integrated into production lines without radical changes.

“People aren’t going to re-engineer their manufacturing lines to have a bunch of 3-meter chambers all over the place,” Einbinder said. Much of the work is still being conducted in OEM and infrastructure company and carrier labs; commercial labs will start becoming more involved once there is an actual standard and certification processes through bodies such as the Global Certification Forum and the PTCRB. Hurtarte noted that OTA testing will require the use of chambers that can be closed; are insulated; and potentially may need to have other features, such as the ability to change temperatures or rotate the device inside. He said that initial production for 5G is expected next year and that scale will ramp up in 2019 and 2020. Part of this will depend on if or when millimeter wave makes it into large-scale devices such as consumer smartphones, versus other applications such as industrial IoT.

5G’s biggest challenges

So all the kinks in those components of 5G will get worked out in LTE and the transition will be a piece of cake, right? Not exactly. There are some major challenges to the success of 5G, which are all interrelated:

  • the move to millimeter wave (mmwave) frequencies,
  • the need for ultra-density, and
  • the question of when the economics of 5G will actually work well enough to take off.

The first of those is perhaps the most obvious: the move to higher frequencies. While low, mid-band, and millimeter-wave frequencies are all expected to be used for 5G, mmwave presents enormous engineering and network planning challenges. Mmwave 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.

Even the mid-band, which carriers like KT are planning to use as a better-propagating anchor in a 5G network that utilizes both 3.5 GHz and 28 GHz, will need far more sites than macro networks have had to have, to this point in cellular evolution for outdoor coverage. Right now, said Lindsay Notwell, VP of carrier and international business at Cradlepoint, the industry is starting to more tightly integrate the use of 5 GHz in a license-assisted access context. CBRS “is nice” at 3.5 GHz, he added, “but that’s still worse than the old 2.4 GHz in terms of propagation characteristics: shorter range, less ability to penetrate.” Given the constraints of the spectrum, then, denser networks are critical to 5G at the mid-band and mmwave. But that presents an enormous investment in fiber and site acquisition.

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.

That means some major changes are going to have to happen in order to make the numbers work for widespread 5G deployment at mmwave. It also means that when operators like T-Mobile US talk about being able to deploy 5G NR at 600 MHz, without the need for such intensive densification, “that has got to be having a major impact on how the other folks in the North American market are looking at where they’re going to be a year from now,” Einbinder said.

Fixed Wireless Applications (FWA) may not be quite as compelling as originally expected. 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.” He added that other considerations are also continuing to be explored, such as the final architecture of the customer premise equipment: from a CPE modem placed inside the house, an intermediate step of an antenna on the outside of the house is connecting to a modem inside the house, rather than just an inside modem.

In short, 5G will have to prove itself in order to earn investment. “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, 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). Network slicing may be of limited use in some regions where net neutrality restrictions apply. LTE, he added, “goes quite a long way, and some operators are saying, ‘How can we get more out of 4G and delay 5G, because it’s going to be really complex in the high bands?‘”