Radio spectrum in the 5G wireless world

What's the buzz around spectrum? Don Sheppard looks at 5G and Canada's latest spectrum auction.

Twenty-five years ago Maclean’s magazine put the spotlight on a wired world, but today it is wireless networking that connects the globe. Traditional wired telephones have become legacy devices, and businesses and consumers now demand that the Internet have high performance, be universally accessible and comparatively inexpensive. In many countries, network providers are looking to a new generation of wireless networks – 5th generation, simply called 5G – which deliver very high speeds (at least 1GHz), significantly lower latency (1 millisecond or less), high density (at least one million IoT connections per square kilometer) and consistent performance.

Limiting this revolution is spectrum resource. All wireless systems use specific frequency bands on the radio spectrum but there is only a limited supply of these bands available. Service providers must compete for access to these frequencies in order to take advantage of the new technologies and profit from the development of new services. Managing the demand for spectrum, including for 5G, is a complex undertaking that requires astute technology forecasting, close attention to competitive business interests and international cooperation. In Canada, the federal department Innovation, Science and Economic Development (ISED) represents national spectrum interests within the International Telecommunication Union (ITU) and has responsibility for assigning frequency bands within Canada.

But why has radio spectrum availability become newsworthy now? Do frequency licensing decisions have any impact on enterprise IT? And, perhaps more importantly, is access to 5G spectrum critical for Canadian industry?

The importance of the radio spectrum

Radio spectrum is important simply because wireless and broadcast communications cannot exist without it. All forms of wireless communications share the radio spectrum, and users strive to minimize interference from within the environment.

Radio spectrum licenses are valuable due to their limited availability – not all frequencies are suitable for all applications. Radio spectrum for FM radio (88 - 108MHz) and broadcast television (54–88 and 174-216MHz) has an obvious value for broadcasters. Other parts of the radio spectrum support cell phones, public safety radio (police, fire and ambulance), marine and aircraft communications, cordless phones, amateur radio, radio control devices, drones, WiFi and many other uses. Some examples of existing frequency assignments, as they compare to 5G are shown in Figure 1 (for the full picture, see a very detailed chart here).

Figure 1. Radio spectrum examples
Figure 1. Radio spectrum examples

The April 2019 auction in Canada of 52 licenses for 5G frequency bands in the 600MHz range provides further evidence of the value of the radio spectrum: in this auction, nine companies purchased 104 licences at a cost of $3.47 billion.

Unlicensed frequency bands are an alternative for some communications use cases. With an unlicensed frequency, users must contend for access and accept the possibility of interference and performance degradation. WiFi, for example, typically uses the 2.4 GHz and 5 GHz bands, which that are also used for a variety of industrial, scientific and medical applications. Reduced WiFi performance is common in locations with lots of independent users (an apartment building, for example).

Licensing of frequency bands for 5G has now started in many countries, including Canada, especially in the low-band range. International harmonization is being handled by the ITU, with the formal ratification of high-bands scheduled for November 2019 at the ITU World Radiocommunication Conference. Access to radio spectrum for 5G will have a major impact on the pace of 5G deployment.

Radio spectrum for 5G applications

Since 5G specifications call for significantly faster speeds, very low latency, massive density, very long battery life and wide coverage including inside buildings, new radio technologies had to be developed. But with 5G, a wide range of applications and devices for smart cars, smart cities, factories and hospitals can be deployed cost-effectively, a benefit that will unlock the full potential of the Internet of Things (IoT). 5G also ensures that growth and performance for current mobile applications, such as on-demand video, can be sustained. In many parts of the world, including rural areas in Canada, 5G wireless will be a cost-effective substitute for wired broadband links.

Since frequency bands have different properties, all radio-based communications involve trade-offs between speed, distance/coverage, density and bandwidth. As Figure 2 shows, lower frequencies support longer distances and are less susceptible to being blocked by physical objects, but this is achieved at the expense of speed and capacity.

Figure 2. Frequency trade-offs
Figure 2. Frequency trade-offs

According to the GSMA, 5G services will require bandwidth in three key bands: low-band is sub-1 GHz, mid-band is 1 to 6 GHz and high-band is above 6 GHz. The sub-1 GHz range will support coverage for longer distances across urban, suburban and rural areas and will help to support IoT services. The 1 to 6 GHz range, which includes spectrum in the 3.3-3.8 GHz band, offers a good balance of coverage and capacity benefits. Frequency bands above 6 GHz are needed to meet the ultra-high broadband speeds, with the 26 GHz and 28 GHz bands currently garnering the most international support.

For a typical 5G mobile broadband system, the capacity and latency are similar to what has been achieved with current 4G networks on the same band. The low-band spectrum, historically used for 2G, 3G and 4G cellular networks and for broadcast TV, includes the 600 MHz band, which is important for 5G. Low-band frequencies will be used to travel longer distances in rural areas and pass through barriers for better coverage in locations such as elevators and parking garages.

New mid-band spectrum, typically in the 3.5 GHz spectrum band, will most likely be provided with bandwidths of 50–100 MHz to support high-capacity, lower latency networks. New 5G use cases will be supported while also providing better wide-area and indoor coverage than is possible with the high-band spectrum. The 3.5 GHz band is considered to be important since is supported by more mature technologies.

The high-band mmWave spectrum (26, 28, 37-40 and 64-71 GHz bands in Canada) is the target for highest performance 5G applications. This high-band offers speed and latency advantages, but is suited only for short distances, does not penetrate buildings and is subject to more interference.

Timely availability of spectrum applies to all frequency ranges for both licensed and unlicensed bands. Licensed bands will be crucial to 5G market development as they allow for better quality control and will also drive the equipment market. Additional unlicensed spectrum may also be used to ease capacity constraints, as it can help operators deliver exceptionally high data throughput in hotspot areas.

Spectrum management is not a simple exercise and poor management can have unintended side effects. For example, there are concerns that 5G networks operating at frequencies in the 24GHz range could degrade the quality of weather forecasting: faint signals emitted by water vapor in the atmosphere at a frequency of 23.8 GHz are monitored by weather satellites and fed into prediction models for storms and weather systems. Another area of concern for some consumers is the potential for health risk associated with radio transmissions, as is highlighted in a recent article in Toronto’s Now magazine.

5G spectrum in Canada

In June 2018, ISED produced a report, entitled Spectrum Outlook 2018 to 2022, outlining its plans to make additional Canadian spectrum resources available for commercial mobile services. Frequency bands identified as priorities are the 600 MHz, 3500 MHz, 26 GHz, 28 GHz, 37-40 GHz and 64-71 GHz bands.

In March 2018, ISED finalized its decisions on the 600 MHz band. In total, 70 MHz of spectrum was made available with 30 MHz reserved for new entrants. The recent auction, as noted above, awarded 104 600 MHz spectrum licenses to nine companies. Telus, for example, won 12 new licences in British Columbia, Alberta, Saskatchewan, Ontario and Quebec, allowing them to provide enhanced urban and rural mobile broadband nationwide. Rogers won 52 licenses covering territories from Newfoundland to the Northwest Territories. Bell Canada decided not to bid for 600 MHz licences but stated they already have sufficient spectrum, such as the 700MHz band, to offer 5G services. According to Telus, the Canadian auction resulted in the highest prices for 600 MHz spectrum in the world, roughly two times as high as the USA on average.

The next step for Canada is the opening up of higher frequency bands. A consultation (SLPB-004-18) was published in June 2018 on revising the 3.5 GHz band to accommodate flexible use for fixed and mobile 5G services. Although decisions on this consultation are still pending, ISED have stated that a 3.5 GHz auction will take place in 2020.

The third phase of 5G spectrum development is for the millimeter wave (mmWave) range. In June 2017, ISED issued a consultation (SLPB-001-17) on releasing mmWave spectrum and asked for comments on making the 28 and 37-40 GHz bands available for 5G fixed and mobile use and the 64 to 71 GHz bands for license-exempt use. An addendum published in June 2018 (SLPB-005-18) added the 26 GHz band to the review process. The 26 GHz and 28 GHz bands, which are adjacent, yield a total of 1.85 GHz of contiguous spectrum. No decisions have been made on this consultation yet and an auction is not expected to take place until at least 2021.

The transition to 5G operation

5G networking is now real: starting on April 11, Verizon launched 5G in Chicago and Minneapolis and, since then, more cities have been added to this list. AT&T has 5G presence in various cities throughout the USA and Sprint launched 5G using its 2.5 GHz spectrum at the end of May. South Korea has also launched 5G services and claims to have deployed more than 54,000 base stations as of May 2019.

The USA is also moving quickly into the high-band systems as shown in its auction for 24 to 28 GHz spectrum: T-Mobile bid for 1,346 mmWave (24 GHz) licenses and AT&T for 831 licenses. A similar high-band auction isn’t expected in Canada until 2022.

5G growth is also closely linked to advances in smartphones, IoT sensors, edge/cloud computing, artificial intelligence, software-defined networks and modern methods for rapid software development, all of which can exploit the capabilities of 5G networks. Samsung, for example, has released its first 5G-compatible phone (the Galaxy S10 5G) though other companies, such as Apple, have not yet delivered 5G compatible devices.

The outcome of auctions for 5G spectrum in Canada are a sign that 5G has moved beyond the research and hype stages, but questions remain concerning how fast 5G will roll out and be adopted. Radio spectrum discussions are currently newsworthy because of the large investments being made, because of the potential for new applications that 5G makes possible, and due to the belief that 5G is important as a national competitive differentiator.

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