Introduction to 60GHz mmWave
Unlicensed mmWave spectrum, commonly referred to as the “V” band, was originally designated for use by the military. In 1994 the FCC released an NPRM establishing the V-Band as 57GHz to 64GHz in line with other global definitions and made it an unlicensed band similar to 5GHz for Wi-Fi. Since that time the FCC has steadily increased the available spectrum to where it is today, offering 14GHz of spectrum from 57GHz to 71GHz, with 71 GHz actually being the lower end of the “E” band.
Despite the huge swath of spectrum made available, use of the V-Band remained limited for a few reasons. In 1994 60GHz mmWave represented a frequency band far higher than what most commercial applications for wireless were using. The most common wireless applications in 1994 were still broadcast TV and cellular systems. Both of these operated in the much lower range of 600MHz to roughly 2GHz bands. Design and operation of 60GHz mmWave systems was very difficult and expensive. The eco-system of components, test gear and more just did not exist. Nor at that time did the applications needed to drive development of the aforementioned ecosystem.
In the late 1990s and early 2000s a gigabit connection was something used almost exclusively in fiber systems and for trunking applications deep in the network core, or to serve select business customers. We had to wait until the late 2000s for the launch of Gigabit services to homes in some Nordic countries and by Google in the USA — and always over fiber. And these launches demonstrated the value of and the interest in consumer Gigabit services.
Next came the WiGIG standard, first proposed by the WiGig Alliance in 2009 and adopted in 2012. This standard established interoperability for commercially developed 60GHz mmWave systems. In 2013 the Wi-Fi Alliance adopted WiGig, standardized with IEEE as 802.11ad, and layered the Wi-Fi or 802.11 MAC layer on top. Still, progress was slow. At the heart the mass adoption of any wireless standard lies implementation and adoption in phones, PCs and tablets. This in turn requires development of an ASIC or chip that offers the PHY and MAC layer functionality on a low-power and low-cost chip (or chipset). Once the chips are available, test programs and labs must be set up to ensure product interoperability. The Wi-Fi Alliance introduced these programs in 2016 and hence fully launched the 60GHz band into the mainstream.
With the initial focus on Wi-Fi applications or use cases, 802.11ad or WiGIG was initially seen as a solution for transmitting HD or 4K video signals around a home. That and the need, in some cases, for a gigabit Wi-Fi network to transfer large files, were the driving forces behind 60GHz.
Since this initial introduction in 2016 another completely different use case has arisen that is now largely driving the 60GHz industry – Fixed 5G. Fixed 5G is not to be confused with 5G New Radio (5G NR) which is the mobility standard in mmWave and operates in the 30 and 40GHz bands. Fixed 5G uses the spectrum, capacities, and unlicensed nature of the 60GHz band and uses it for high-capacity use cases such as video backhaul (for security and other applications), Wi-Fi backhaul and municipal networks in Smart Cities. Fixed 5G is also being used to deliver gigabit services to homes and businesses. As the market moves to gigabit services, the 60GHz band remains the largest amount of contiguous spectrum available and is well suited to delivering gigabit per second services in low to high-density population areas.
What is 60GHz mmWave
While it was adoption by the Wi-Fi Alliance that breathed life into the 60GHz ecosystem, it is the promise of fixed 5G that is driving the industry today. The 5GHz Wi-Fi band and products have been used for Fixed Wireless Access for decades, offering increasing speeds as the Wi-Fi standard evolved. The problem though is simple – the 5GHz band only offers a total of 450Mhz of spectrum and over the years has become increasingly congested, even more so since wireless local networks have increased their use of this spectrum. Between limited spectrum and interference, the 5GHz band is not suitable for delivering on the Gigabit promise.
Systems operating in the V-Band support 5Gbps over 1GHz or 2GH channels today. New products are being developed that will use even larger channels and higher order modulations to deliver 8Gbps and more.
In addition, 802.11ad was designed for indoor and hence not a lot of time was spent trying to see how far one could go beyond a few dozen meters. Thus the shorter range of high-frequency designs coupled with the oxygen absorption effect centered at 61GHz raised concern that fixed 5G in the V-band would always be severely range-limited.
Oxygen Absorption Side Bar – One of the peculiarities of the 60GHz mmWave band lies in an effect called oxygen absorption. Basically, the oxygen molecule that exists in our atmosphere, O2, has a geometry that is ideal for absorbing millimeter waves with a peak at 61GHz. This reduces the effective range of 60GHz systems more so than surrounding bands. Deploying in the upper sections of the 60GHz band at 65 or 66GHz and above can avoid this effect.
Introduction to 60GHz mmWave
Unlicensed mmWave spectrum, commonly referred to as the “V” band, was originally designated for use by the military. In 1994 the FCC released an NPRM establishing the V-Band as 57GHz to 64GHz in line with other global definitions and made it an unlicensed band similar to 5GHz for Wi-Fi. Since that time the FCC has steadily increased the available spectrum to where it is today, offering 14GHz of spectrum from 57GHz to 71GHz, with 71 GHz actually being the lower end of the “E” band.
However, this limitation is also an advantage when deploying in dense urban settings: the limited propagation characteristics of 60GHz mmWave lowers the potential for interference dramatically.
More and more people are learning about the V-band and its significant capacity capabilities, but do express concern about the limited service range. However, this has not turned out to be the case. With the introduction of systems based on WiGig and targeting outdoor longer-range uses, these products are reliably reaching from 300 to 500 meters in multipoint systems and as far as 1 km for point-to-point (PtP) applications.
How is 60GHz mmWave used today?
Given the burgeoning demand today for gigabit-speed connectivity, the V-Band and even E-Band (70/80GHz) are experiencing huge growth in terms of the number of network products available and advances in technology are contributing to lower cost systems. Both of these factors are spurring adoption and driving volume production and deployments. Therefore, what began as somewhat limited fixed 5G services in the V-band has now grown to a large array of “Gigabit Wireless Aceess” services, with the primary applications being residential SFU, businesses, MDUs and Smart Cities.
In Smart City applications, 60GHz V-Bands systems are used extensively for connecting video security cameras where an Ethernet or fiber connection may not be available. Cameras are now at a minimum HD, and the industry is moving to 4K and even 8K resolution, which is driving the capacity demands from cameras ever higher – as much as 50 to 100Mbps per camera. In addition, many cities are seeing a resurgence of Public Wi-Fi. These next-generation outdoor APs are themselves capable of delivering 1.4 Gbps or higher, meaning connecting such an AP requires a gigabit connection – and in the wireless domain, only 60GHz can support that.
As noted above, the number and types of products being developed for the 60GHz band is exploding. This frequency band is powering point to point, point to multipoint and mesh topologies. Furthermore, new industry standards are being introduced to standardize and expand the use of 60GHz. Organizations such as the Telecom Infrastructure Project (TIP), backed by Meta, introduced a Fixed 5G standard based on the V-Band called Terragraph. Systems complying with the Terragraph standard are based on the latest generation 60GHz chips specified by the IEEE and certified by the Wi-Fi Alliance – 802.11ay. This next generation of wireless gigabit systems will have several new features designed to improve operation outdoors.
The Future of 60GHz mmWave
With the 60GHz mmWave ecosystem thriving, being propelled by the need for gigabit connectivity, the future is bright for 60GHz. Many people see a parallel with the 5GHz band from ten years ago, but with an even brighter future. In the 5GHz band RF beams are wide and reflected easily and spectrum is limited, both of which contribute to the massive congestion 5GHz sees today. However, 60GHz has no such limitations. Because the RF beams are typically one to 5 degrees, only cover short ranges, are not reflected and have 14GHz to work in, congestion and hence interference in the 60GHz mmWave band is almost impossible now and in the future.
Additionally, the newest standard (802.11ay) entering the market for Fixed 5G systems will enable a quantum leap forward in performance. The advent of Terragraph and the interoperability testing planned by the Wi-Fi Alliance will only serve to drive higher adoption, resulting in massive volumes pushing prices down even further. Chips based on 802.11ay will not only be used for outdoor Fixed 5G systems, but for phones and tablets as well.
The V-Band at 60GHz and its increasing use and widespread adoption is not just happening randomly. It starts with a market demand for capacity. The insatiable need for more and more bits per second has made the world we live in a Gigabit World. To meet this demand, the wireless ecosystem turned to the only spectrum that is capable of delivering on the gigabit promise – 60GHz mmWave or the V-Band.
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