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How does mmWave fit into 5G?

Is it really cost-effective or practical for the mmWave bands (26 and 28 GHz) to deliver commercial promise to 5G services?

The 26 GHz and 28 GHz bands, the millimeter wave (mmWave) band is a short wavelength, apt to deliver greater speeds and lower latencies. This in turn makes data transfer efficient and seamless as the current available networks work optimally only on lower-frequency bandwidths.

Many initial 5G deployments are at frequencies similar to 3G/4G mobile networks and Wi-Fi. This also means that many existing antenna sites can be reused for 5G. While low- and mid-bands provide wide area coverage and each has a limited bandwidth, 5G mmWave provides greatly increased bandwidth in localized areas for each user, and enables higher density of users. 5G mmWave refers to the higher range of radio frequencies, supported by 5G.

When it comes to data speeds, these bands fail to hit peak potential needed for a true 5G experience. The mmWave is considered the quintessential piece in the 5G jigsaw puzzle by mobile service providers.

The Indian satellite companies had reiterated that the Indian government refrain from auctioning mmWave satellite spectrum in the 28 GHz band for 5G mobile services. The 28 GHz spectrum is currently being used exclusively by satellite players, and it is also being sought by the telcos to be part of the 5G spectrum auction. They have consistently insisted that without these airwaves, 5G deployment costs would surge and make the ultra-fast wireless broadband service unaffordable in the country.

TRAI has recommended usage of spectrum in 26 GHz and 28 GHz bands on sharing basis for satellite and mobile services. The Authority has contended that co-existence between terrestrial network operators and satellite service providers in the mmWave band of 27.5–28.5 GHz is essential for the optimum use of airwaves. “The Satellite Earth Station Gateway (for satcom) should be permitted to be established in the frequency range 27.5–28.5 GHz at uninhabited or remote locations on a case-to-to-case basis, where there is less likelihood of 5G IMT services to come up. Both international mobile telecommunications (IMT) and satellite bands can co-exist. That has to happen for the efficient use of spectrum. Such a move would encourage buyers – both telcos and satcom players – and eliminate the possibility of a major chunk of such airwaves to remain idle,” observed TRAI.

Satcom Industry Association (SIA) has expressed serious concerns on the TRAI recommendations to include 27.5–28.5 GHz and 3.60–3.67 GHz bands in the 5G spectrum auction. The association had urged the regulator to limit the inclusion of mmWave spectrum in the 5G auction as 27.5–31.0 GHz and 17.7–21.2 GHz bands have been preserved for satellite-based broadband services globally. The industry body pointed to Europe’s 5G Roadmap, which is built on the International Telecommunication Union’s decision to hold these bands for satellite-based broadband services. ITU too has identified the 26 GHz band for 5G mobile services and not the 28 GHz.

SIA-India has also appealed that the 330 MHz of spectrum in the 3.3–3.67 GHz band is enough to satisfy India’s mid-band 5G needs, while ensuring a competitive auction. India has three private mobile network operators holding 90 percent of the total market share. These three will be able to secure the available spectrum, roughly 80–90 MHz each, while leaving the remaining 10 percent to state-owned enterprises.

On the other hand, COAI has expressed keenness that the 28 MHz band be made available for 5G mobile operations in the upcoming spectrum auctions. Interestingly, there is a lack of consensus among operators themselves on the allocation of spectrum for 5G in mmWave.

Experts’ take on the issue. According to a report by UK-based research firm, Plum Consulting, satellite deployments in the full 28 GHz band (27.5–29.5 GHz) can contribute to significant economic benefits for emerging markets in the Asia-Pacific region. The report says the provision of high-speed broadband connectivity via satellite, using the 28 GHz band in India, stands to benefit the country with an annual GDP increment of up to USD 184.6 billion by 2030. Important economic sectors can unlock the unique benefits of satellite broadband, including land transport, aviation, maritime, residential broadband, and even powering 5G terrestrial infrastructure where there is no fiber available.

Not reserving the 28GHz band exclusively for satellite communications runs the risk of inviting such ramifications that may in the long run jeopardize plans to connect the entire country. The 28 GHz band being made fully available for satellite broadband in Europe, China, Australia, Africa, Latin America, the UAE, and growing number of countries, will help India in connecting its vast economy, transport systems, public services, and businesses to the global digital economy. This decision will also translate into billions in GDP growth and to its ability to meet the demand for internet access everywhere in a cost-effective way.

In contrast, GSMA in its report, The Impact of mmWave 5G in India, way back in 2020, had estimated that over the period 2025–2040, mmWave-enabled 5G will deliver USD 150 billion in additional GDP for India. The manufacturing sector will see the greatest impact, accounting for about a fifth. The healthcare sector will also benefit greatly from mmWave-enabled 5G, with an impact of approximately USD 4 billion.

According to GSMA, mmWave plays an underlying role in unlocking the full potential of 5G. It notes that 5G mmWave delivers increased bandwidth, fast data speeds, and lower latency to users, particularly benefitting densely populated areas, such as campuses and entertainment and sports venues, to increase network capacity. In November 2021, GSMA announced the formation of the global accelerator initiative along with China Unicom, NTT DoCoMo, Telstra and TIM, as well as Verizon and Qualcomm. Ericsson is also part of the effort. GSMA cites figures showing that a combined mmWave and 3.5 GHz network is estimated to contribute savings of up to 35 percent in total cost of ownership compared to the sole use of sub-6 GHz bands. It also facilitates the expansion into new areas, such as fixed wireless access (FWA), with fiber-like speeds.

And GSA too, is in favor of all frequency bands including mmWave up for auction, so that the terrestrial networks and satellite systems can co-exist in the band. In a letter dated May 3, 2022, to the DoT secretary K Rajaraman, GSA president Joe Barrett had expressed that “GSA is fully supportive of auctioning of all spectrum bands as recommended by the Telecom Regulatory Authority of India,” adding that the department should make available all these spectrum bands for 5G services at the earliest.

Amidst this tussle, doubts are creeping into the mmWave business case itself. Question marks are appearing over the use of mmWave technology for 5G, with growth in investments in the sector slowing last year.

While more than 100 global operators have access to mmWave spectrum and are investing in the technology, revenue growth slowed in 2021 compared to the two previous years, according to research by Dell’Oro Group. Revenue growth for the mmWave market increased exponentially in both 2019 and 2020, mmWave revenues increased 15 percent to 20 percent in 2021, propelling 5G NR mmWave to account for 1 percent to 2 percent of total sub-6 GHz plus mmWave RAN revenues.

The mmWave spectrum bands are too fragile. This means that they can be easily disturbed through objects and other things, such as trees, walls, etc. Very-high-frequency 5G signals do not travel very far and do not transition very well from indoors to outdoors. However, massive MIMO and beamforming ensure that strict line-of-sight is not a requirement to make use of mmWave. An mmWave signal may not be able to penetrate deep into buildings, but it will bounce around them to ensure a decent signal. Indoors, people will just have to rely more on sub-6 GHz and low-band signals. Thus, the telcos will have to invest more in small cells, which would be very expensive if they want to offer mmWave 5G in a complete city or town.

It is not just in India, but the telecom operators across the world will look to go for 5G rollout with sub-6 GHz bands because it will be more practical for the users. Further, it will also cost less to the telcos, compared to mmWave 5G.

Also, most users may not even have the need for sub-6 GHz 5G networks, if they live in a strong 4G network coverage zone. But even if the users do want to test out 5G, the need for 1 Gbps mmWave 5G speed is not there for say, browsing Instagram. Investing in mmWave 5G may not be as good an idea for the telcos. No doubt, the mismatch between CapEx and data consumption, when comparing the sub-6 GHz and mmWave spectrum, will evolve gradually over time – global 5G NR mmWave revenues are projected to reach USD 1 B to USD 2 B by 2026.

The mmWave 5G will be more attractive for the enterprises and smart facilities, which want to create an internal network for communication.

Having said that, US carriers are particularly keen on the technology. All of the three major US 5G operators hold mmWave spectrum in their arsenals, although Verizon placed the biggest bet on the higher-spectrum bands. And it is also a key part of rollouts in China and Japan. Eventually, it will be used across the world to varying degrees too although not every 5G network will necessarily use mmWave technology, at least not all of the time.

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