The global development of 5G hit a major milestone in December 2017 when 3GPP approved the non-standalone variant of the 5G New Radio specification. While operators around the world tested pre-standard equipment and deployment scenarios, the formal adoption set in motion concrete plans for commercial deployment later this year. To support fast commercialization of new 5G services, service providers continue to upgrade LTE networks to take advantage of the spectral and user experience benefits of technologies like carrier aggregation, Licensed Assisted Access, 4X4 MIMO and 256 QAM–LTE Advanced sites, using radio equipment available on the market, can be upgraded to standard compliant 5G through an over-the-air software update. As commercial 5G becomes more broadly available in 2019, device availability is expected to expand the reach of next-generation network experiences that take advantage of multi-gigabit-per-second throughput and very low latency. On the horizon is standalone 5G, which couples a brand new RAN with a brand new core network. Powerful NFV and SDN solutions, coupled with open source hardware and software, will be implemented over time to gradually automate network operations to optimize use of spectrum and network resources fundamentally shifting the economics of delivering mobile data.
The current broadband landscape is marked by a continuously increasing demand for mobile data as talk and text give way to streaming video as the go-to consumption driver for consumers. Simultaneously, enterprises are slowly moving toward embracing a mobile-first workplace that swaps out wired desk phones for bring-your-own-device. At the same time, the internet of things (IoT) is a booming with projections unanimous in an outlook that billions of new IoT devices will hit global networks in coming years. The implications here are mobile networks will need to support not only more traffic in total, but also more uplink traffic from a huge variety of low- and high-power devices. Not only to deliver a better end-user experience, but also to lower the cost of transmission by more efficiently using network and spectral resources, 5G an is an imperative for operators.
Chapter 1: Standardizing 5G NR
The industry hit a major milestone in December with the adoption by 3GPP of the non-standalone 5G New Radio (NR) specification, which immediately prompted operator announcements of standard-compliant services, as well as vendor launches of spec-compliant equipment. The NSA 5G NR standard uses updated radio equipment supporting a new 5G carrier, and interworks the new RAN with the LTE evolved packet core network. The next major step is the standalone 5G NR specification, which will see major advancements made at the network core.
Chris Pearson, president of industry trade association 5G Americas, called completion of the NSA 5G NR spec something that “really got the industry going. Really, the next phase is going to be the full 3GPP Release 15, which is expected in June of 2018, which will again provide a lot of additional progress. After that there’s additional work when we move to 3GPP Release 16. The expectation is to make sure that is completed by December 2019 to make sure everything is ready to be submitted to [the International Telecommunication Union].
Pearson said the standalone 5G architecture, as well as the content of Release 16, will better define 5G-related technologies like end-to-end network slicing, ultra reliable, low latency communications (URLLC), and the network architecture for the IoT family of use cases. Really 15 fills in pretty much everything that hasn’t been done for 15 that is required to meet the submission to ITU.” While the 5G standard is still a work in progress, the NSA variation gave operators the framework to expand trial activity to be compliant with the standard while honing in on more articulated commercialization plans.
Chapter 2: The current state of operator trials
Last year Verizon tested 5G fixed wireless access in 11 U.S. markets, which the company said included “several hundred cell sites that cover several thousand customer locations.” Now Verizon says it will use that technology to deliver residential broadband services in three to five markets this year. The carrier will make the commercial service available first in Sacramento, Calif., during the second half of 2018. In terms of use cases, Verizon specifically named broadband, mobile and IoT, along with applications including 3D and virtual reality. According to the carrier, “the market opportunity for initial 5G broadband services [is]approximately 30 million households nationwide.” This 5G application taps Verizon’s millimeter wave spectrum holdings, which, in December, Verizon CFO Matthew Ellis said exceeding expectations in “commercial-type tests.” He said spectrum propagation has been better than expected in trials.
AT&T plans to deliver mobile 5G services based on the 3GPP 5G New Radio (NR) standard in an least a dozen markets this year. According to the company, the mobile service will leverage existing network infrastructure that supports its gigabit LTE offering, which the company refers to as 5G Evolution The fixed wireless 5G trials began in Austin using pre-standard equipment, and expanded to Waco, Kalamazoo and South Bend. Those tests proved out use of millimeter waves to deliver residential and enterprise use cases to multiple-dwelling units, small businesses and education customers.
T-Mobile US has focused its 5G talking points around touting its nationwide 600 MHz spectrum portfolio picked up in an FCC auction last year, which CEO John Legere said his company will deliver. On the millimeter wave side, T-Mobile US connected a Nokia base station with Intel’s 5G Mobile Trial Platform using the 28 GHz band in an outdoor environment in its hometown of Bellevue, Wash. For that test, Nokia provided its commercially-available AirScale equipment, which connected to Intel’s 5G Mobile Trial Platform, which uses the chipmaker’s radio frequency integrated circuit to provide broad spectrum support for 5G-related testing activities.
Sprint has put particular emphasis on its 2.5 GHz holdings as an opportunity for relatively low-band 5G deployments. Sprint also is tapping into higher spectrum bands in its 5G network trials, including the 73 GHz band in conjunction with vendor Nokia and the 15 GHz band with Ericsson. Sprint CEO Marcelo Claure and CTO John Saw in February discussed the carrier’s roadmap to delivering a mobile 5G service ahead of planned deployment on the live network later this year. “When you look at our 2.5 [GHz] spectrum,” Claure said, “…that is the low-band of 5G. We’re not going to have the same propagation issues that our competitors are going to have. I could not be more excited. We can roll out 5G just basically by utilizing our towers and our small cells and the entire network plan we have.”
CTO John Saw provided a little more color on the carrier’s path to 5G, noting that 128-element massive MIMO antennas, equipped with vertical and horizontal beamforming form the basis of that evolution. “Our path to 5G is going to be coming through massive MIMO,” Saw said. “Because of our strong spectrum position…we’re able to basically use half these antennas for LTE and simultaneously use the other half for 5G. Essentially you’re killing two birds with one stone. You can turn on 5G with a software upgrade in a few months.”
Chapter 3: What spectrum is 5G spectrum?
The need to deliver more capacity is predicated on access to new spectrum. In addition to tapping the unlicensed 5 GHz band via LAA, spectrum sharing is a topic of major interest in the U.S. The 3.5 GHz band, in the U.S. called the Citizens Broadband Radio Service (CBRS), is the subject of FCC discussion around allowing non-incumbent users access to the frequencies. The band is current used by the Department of Defense and fixed satellite operators, but the telecom regulator is considering rules that would allow a three-tiered, priority access spectrum sharing system that would allow service providers and non-carrier entrants to acquire and deploy in the band. Globally the 3.5 GHz band is being a regarded as a mid-band for 5G deployments. Along with millimeter wave frequencies that provide ultra-high-capacity, it’s clear there may be no one mix of optimal 5G spectrum, but it is a mix including low-, mid- and high-band spectrum.
“There are different viewpoints about what would be considered the initial deployments of 5G,” Pearson said. “I think that’s good for the industry.” He said, generally, 5G deployment plans will align with an operators’ holdings. “In other parts of the world that will be early, you’ll see the mid-band play a role In North America you’re looking at deployments of low-, mid- and high-band spectrum all based on the announcements we’ve seen from the four national carriers.” In APAC, the mid-band “ is probably considered at the forefront. Then after that it would be all the way up toward the millimeter wave.”
In the U.S., early millimeter wave trials focused on a fixed wireless use case, which is what Verizon is commercializing this year. But the long-term goal of using millimeter wave for a mobility use case is the subject of some concern given the challenging propagation characteristics and the complexity of RF front end design, as well as the role of hand-block and other factors.
Durga Malladi, Qualcomm Technologies senior vice president of engineering, said the chipmaker developed a millimeter-wave compatible platform in a smartphone form factor to help “overcome industry skepticism. Another key component to 2019 launches is the progress toward functional silicon in the mobile device form factor, which our first data connection operating in the 28 GHz millimeter wave band achieved.”
Chapter 4: Gigabit LTE is a key 5G enabler
5G is clearly a sea change in wireless that will profoundly influence network investment and operations for decades; but LTE, as the name Long Term Evolution suggests, has significant room for growth. Consider what we saw in 2017. In January Australian operator Telstra commercially launched a gigabit LTE network that relies on LTE Advanced Pro features to deliver enhanced mobile broadband experiences. To pull this off, Telstra worked with Ericsson on the network infrastructure piece to connect a Netgear mobile router equipped with Qualcomm’s X16 LTE modem. In the 12 months that followed this first launch of gigabit LTE, 44 additional operators in 26 countries–including all four major operators in the United States–have, to varying degrees, begun deploying gigabit LTE. In that same timeframe, OEMs have expanded the ecosystem of gigabit LTE compatible devices to include flagship smartphones like the Sony Xperia XZ Premium, LG V30 and Samsung’s Galaxy S8, S8+ and Note 8.
The combined features that de- liver gigabit LTE were enhanced and adopted by standards-setting body 3GPP in October 2015 with the group’s Release 13. The primary building blocks of gigabit LTE are:
- 4X4 multiple-input, multiple-output (MIMO), which uses four antenna ports at the transmitter and receiver to multiply the capacity of an RF link. With compatible user equipment, 4X4 MIMO can transmit four simultaneous data streams delivering faster mobile data speeds.
- Carrier aggregation effectively joins together non-contiguous bits of radio spectrum, both licensed and unlicensed, into a wider channel. Compatible with both TDD and FDD LTE networks, intra- and inter-band carrier aggregation can combine up to five component carriers of 20 megahertz channel widths.
- 256 quadature amplitude modulation (QAM) manipulates phase and amplitude of wave- form to allow a higher bit rate per hertz. The higher the order of modulation, the more bits per modulation symbol are transmitted.
The result of combining 4X4 MIMO, carrier aggregation and 256 QAM is faster data throughput over a mobile network, but it’s important to note that networks branded as gigabit LTE don’t necessarily provide 1 Gbps speeds. The actual peak speed depends on the configuration of the network. For instance, a network equipped with a dedicated download channel, 4X4 MIMO, 256 QAM and aggregation of a 15 megahertz LTE channel with a 5 megahertz LTE channel would result in a peak theoretical speed of 400 Mbps. A network with a shared download and upload channel, 4X4 MIMO and 256 QAM that aggregates three 20 megahertz LTE channels could hit speeds in the range of 730 Mbps. A network with a dedicated download channel, 4X4 MIMO, 256 QAM, but aggregating four 20 megahertz spectrum channels–one 20 megahertz channel of licensed LTE spectrum and three 20 megahertz channels of unlicensed 5 GHz spectrum–could hit the 1 Gbps mark.
Malladi highlighted in a recent blog post the role of LTE in supporting 5G. He said “continued advancements in LTE technologies…are establishing the foundation for 5G, as they will play key roles in providing many essential services for 5G. Gigabit LTE deployments leveraging LAA will improve user experiences and deliver better network efficiencies, complementing initial 5G NR deployments for enhanced mobile broadband. Other new LTE Advanced Pro technologies will accelerate the mobile expansion to new verticals, such as LTE IoT, C-V2X, drone communication and more.”
“5G Americas is really positive, bullish, on the roadmap of innovation for LTE even as 5G gets a lot of the headlines,” Pearson added. “We’ve been promoting and explaining the great innovations of LTE for quite some time and we will continue to. When we look at LTE and the advancements that LTE is coming up with…we look at LTE as the mobile wireless foundation for 5G. Increasing the capabilities from the technical side will then increase what the user is getting on the user side is incredibly important to our industry. We want to continue to push the envelope and go towards the LTE Advanced Pro technical capabilities so that the users have a wonderful experience.”
Chapter 5: NFV, SDN and the mobile edge
The long-term vision of 5G is an automated network capable of zero-touch provisioning of network, spectral and compute resources needed to precisely meet the service requirements of applications ranging from an NB-IoT connected smart water meter to an ultra-reliable low latency connection supporting autonomous drone movements. To create these end-to-end network slices, 5G networks will gradually become completely virtualized. We’re seeing the movement in this direction today with increasingly widespread network functions virtualization and software-defined network implementations, as well as with the deployment of virtualized radio access network infrastructure, which swaps expensive, proprietary signal source equipment for software running on commercial off-the-shelf server hardware.
Another key trend is the distribution compute power. 5G takes a cloud-native approach to network design. While the cloud is usually associated with services and hardware centralized in a remote data center, the ultra low latency of 5G will command a movement of compute power toward the mobile edge. The most common example of the importance of mobile edge computing (MEC) is autonomous driving–centralized cloud services will be used for things like in-car infotainment and navigation, for example, but life-or-death functionality like braking or swerving won’t wait for a round-trip to a data center. That kind of decision making will require communications with an analytics and insight platform that’s physically closer to the end user.
In a recent report, Senza Fili Principal Monica Paolini said 5G will be an inflection point for automation. “The new automation solutions and platforms are no longer restricted to tackling simple processes; they allow operators to manage the increased complexity of wireless networks, deepen their understanding of how their networks work, better serve their subscribers, and take full advantage of the new technologies. The new breed of automation is much more than avoiding boring tasks and saving money. It is a core enabler that spreads across wireless networks end-to-end and deeply changes operations at both the technical and cultural level.”
Conclusion
With dynamics ranging from spectrum and radio investments to slowly gaining software-control of increasingly automated network, Pearson said it’s important for industry leaders to exchange ideas and focus on developing an ecosystem-driven approach. That’s the goal of 5G Americas’ upcoming 5G New Horizons Wireless Symposium in Austin, Texas, May 16-17 at the Austin Convention Center.
“5G is a technology that has tremendous capabilities,” Pearson said. “It’s going to be a technology that doesn’t just change our experience with a smartphone but has the opportunity to change the connected society and address the various vertical markets. We have people from all over the world to share their viewpoints and ideas and collaborate regarding 5G.”
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