It's time to plan and allocate harmonized 5G spectrum in low, mid and high bands says Berge Ayvazian, Senior Analyst/Consultant at Wireless 20/20.
Just before the start of the year-end holidays, 3GPP ratified the 5G New Radio (5GNR) Non-Standalone (NSA) specification during a RAN plenary meeting held in Lisbon, Portugal. The 5G NR specifications for Non-Standalone (NSA) operation are included in the 3GPP’s Release 15 where the control of the 5G radio service will be “anchored” in the LTE Evolved Packet Core while 5G NR carriers are used to boost data-rates and reduce latency. This initial standard covers both fixed and mobile applications and completes the common part of 5G NR in both NSA and SA modes, laying a solid foundation for a global unified 5G system with worldwide market scale. As promised earlier in 2017, the accelerated timeline and release of the NSA 5G NR specification by year-end 2017 will enable the next phase of equipment availability and movement to interoperability testing and will provide the basis for initial 5GNR NSA products to be made available in 2018 and enable the initial commercial deployment of 5G enhanced mobile broadband networks based on the 5GNR NSA technology in early 2019.
The global 5G standard for a new OFDM-based air interface is designed to support the wide variation of 5G device-types, services, deployments and spectrum bands. The 5GNR NSA specification also laid out key 5G spectrum bands including:
- 617MHz to 698MHz (Band 71)
- AWS (Band 66)
- 3.3GHz to 4.3GHz
- 4.4GHz to 4.99GHz
- 24.25GHz to 29.5GHz
- 37GHz to 40GHz
This makes 2018 an even more critical year to plan and allocate harmonized 5G spectrum in low, mid and high bands. Wireless 20/20 believes that a balanced portfolio of 5G licensed and unlicensed spectrum will be required to support 5G network deployments worldwide over the next decade. As indicated in the following exhibit, each spectrum band has specific characteristics that make it suitable for certain deployment scenarios. While the low range of spectrum has very good propagation characteristics that make it feasible for large area coverage, it has limited capacity due to lack of available spectrum and component design considerations. The mid-range of spectrum provides a type of coverage more feasible for urban deployment, with increased capacity. The high-band of spectrum is more limited in coverage, but could provide very high capacity due to the amount of unused spectrum available at these frequencies. Given the diversity of future applications no single band can meet every 5G requirement.
In its new report, Wireless 20/20 examines the state of sub-6GHz spectrum availability in the US as it applies to 5G Mobile deployments. By asking “What spectrum bands will US operators use for Mobile 5G?” we examine not only the current spectrum holdings of the top 4 US mobile operators, but also, the potential availability of suitable spectrum for mobile 5G deployment in the USA. This report provides an overview of the dependencies between the 5G applications spectrum requirements and spectrum bands that may be attractive for deployment of 5G Enhanced Mobile Broadband services. Although much of the dialogue on 5G spectrum in the US has focused on millimeter (mmWave) spectrum, it is not clear that mmWave spectrum is suitable for mobile network deployment in the near to mid-term future.
In 2016, 3GPP published TR22.891 which contains more than 70 different use cases for potential 5G requirements, categorized in to three different groups; Enhanced Mobile Broadband, Critical Communications and Massive Internet of Things. Wireless 20/20 has added a new paradigm for 5G Use Cases in the following exhibit, including Fixed Wireless Access as the initial effort by US operators to testing 5G technologies as a more cost-effective approach to expand the coverage and capacity of their fixed broadband networks. We believe 5G FWA using mmWave spectrum will be the first application for commercial service beginning in 2018, and will serve as a test-bed for the other three use cases thatwill require low and mid-range spectrum for deployments in 2020 and beyond.
This is exactly why Verizon is concentrating on the Fixed Wireless Access use case in order to develop an ecosystem of vendors to advance mmWave technology and showcase the building blocks that will ultimately be necessary for the commercial deployment of mobile 5G. The array of technologies that need to be developed, miniaturized and optimized include antenna technology, RF front end circuits, including mmWave power amplifiers and filters, as well as the associated PHY and MAC digital circuitry capable of utilizing mmWave for the over-the-air interface. All this has to ultimately be developed in low power semiconductor technology for integration in hand held, battery operated smartphones.
Wireless 20/20 believesthe 5G Fixed Wireless Access use case is an ideal application to enable the industry to develop, and test many of the piece-parts that will ultimately be integrated in smartphones. Most industry analysis and observers will agree that it is unlikely to see mmWave 5G technology be integrated into smartphones in the next two years. Low-band wireless signals travel further and penetrate obstacles like buildings better than the mid-band and high-band spectrum. But sub 6-GHz spectrum will be necessary if the promise of 5G Enhanced Mobile Broadband is to be met by 2020.
It is clear that low- and mid-band spectrum bands are emerging as critical ingredients for 5G mobile networks to be deployed nationwide. Wireless 20/20 recognizes that mmWave bands offer a huge amount of spectrum, which could deliver orders of magnitude improvements in network speed, capacity and latency. The tradeoff is that mmWave spectrum generally requires line-of-sight, can be affected by weather, and offers relatively limited coverage. Providing nationwide mobile 5G service in these high spectrum bands will also require the deployment of large numbers of small cells—and the formula has yet to be developed to do this at scale.
The FCC also recognizes the importance of low- and mid-range spectrum in the 5G race, and recently proposed policies to increase the usability of additional 3.5 GHz band spectrum for 5G. T-Mobile and the CTIA have been leading an effort to make the 3.5 GHz CBRS band more ‘5G friendly’ by lengthening the terms of the licenses and expanding the geographic service areas. Also in August, the FCC opened an inquiry into new opportunities in the 3.7-4.2 GHz band, to be used for the “next generation of wireless services”. This effort is also backed by Google and several wireless ISPs, who would want to use this spectrum allocated for fixed wireless services.
Wireless 20/20 believes that the time is now for the planning and allocation of harmonized spectrum in sub-6 GHz low- and mid-bands to help carriers successfully deploy 5G enhanced mobile broadband and massive IoT services nationwide.
Hear more from Berge Ayvazian at 5G North America, taking place in Austin, Texas, May 14 - 16 2018.