What is 60GHz mmWave?
In this day and age the demand for more and more bits per second is at a record high. Words such as ‘Gigabit’ are now commonplace in wireless transmissions and the market is unwilling to accept anything less. 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.
Looking at the different radio frequencies that our modern wireless technologies use, you may be hard pressed to come up with applications of the 60GHz frequency. The emergence of new applications such as those from Siklu, MikroTik and Ubiquiti promise to soon bring 60GHz into the mainstream.
Introduction to the 60GHz mmWave
The 60GHz frequency is an Extremely High Frequency (EHF) which falls in the V band, as designated by the Institute of Electrical and Electronics Engineers (IEEE). The 60GHz frequency is also considered a millimeter-wave (mmWave) frequency. In 1994 the E band was established as 57GHz to 64GHz, and made an unlicensed band similar to 5GHz for Wi-Fi. Since then the available spectrum has steadily grown to where it is today, offering 14GHz of spectrum from 57GHz to 71GHz, the lower end of the E band.
In spite of the wide spectrum made available, use of the V band remained limited. Design and operation of 60GHz mmWave systems was challenging and cost-inefficient. The most common wireless applications were still broadcast TV and cellular systems which operated in the much lower range of 600MHz to roughly 2GHz bands. At the time, the applications needed to drive development of the ecosystem of components, test gear and more did not exist.
Fast forward to 2009, the WiGig standard was first proposed by the Wireless Gigabit Alliance and later adopted in 2012. This standard established interoperability of commercially developed 60GHz mmWave systems. In 2013 the Wi-Fi Alliance adopted WiGig, named it 802.11ad and layered the 802.11 MAC layer on top. After the manufacture and testing of chips that could offer the MAC layer functionality, the Wi-Fi Alliance introduced these programs in 2016, hence fully launching the 60GHz band onto the mainstream.
Since its introduction in 2016, a whole new use case – fixed 5G – has emerged, which is currently driving the 60GHz sector. Fixed 5G makes use of the 60GHz band's spectrum, capabilities, and unlicensed nature for high-capacity applications including security video backhaul, public Wi-Fi backhaul, and municipal networks in Smart Cities. Fixed 5G is also being used to provide Gigabit Internet access to homes and businesses. As the market shifts to Gigabit services, the 60GHz band, with its vast spectrum, is the most contiguous spectrum available and is best suited to meet these Gigabit per second requirements.
How the 60GHz mmWave is being used today
While it was adoption by the Wi-Fi Alliance that breathed life into the 60GHz ecosystem, it is now the prospect of fixed 5G that is propelling the sector forward. Fixed Wireless Access has been using the 5GHz Wi-Fi band and products for decades, with rising speeds as the Wi-Fi standard progressed. The issue, on the other hand, is straightforward: traffic congestion.
The 5GHz band comprises a total of 450 Mhz of spectrum and has become increasingly congested over time. The 5GHz frequency is unsuitable for delivering the much-needed Gigabit speeds due to restricted spectrum and interference.
There has always been concern about how far these products can go when people hear about this band and its great capacity potential. It is an unavoidable fact that systems operating at these high frequencies require line of sight (LOS) and have a limited range due to physical laws, compared to their lower frequency equivalents.
Furthermore, because WiGig developed products are intended for indoor usage, little research was spent determining how far they could travel beyond a few dozen meters. When these products and the inherent shorter range of high frequency designs were combined with the oxygen absorption effect concentrated at 61GHz, there was concern that the industry would always be range constrained.
Oxygen Absorption Side Bar
The effect of oxygen absorption is one of the peculiarities of the 60GHz mmWave band. The oxygen molecule found in our atmosphere has a shape that makes it excellent for absorbing mmWaves with a peak at 61GHz. The effective range of 60GHz systems is reduced more than that of neighboring bands as a result of this. Deploying in the upper 60GHz range at 65 or 66GHz and above can help avoid interference.
60GHz mmWave graph
Today with the heightened demand for Gigabit connectivity, the V band and even E band (70/80GHz) are experiencing huge growth in terms of number of products available and the rapidly reducing price points – all working in unison to spur adoption and drive volume. Entering the market as Fixed 5G, the two primary applications for this band remain Gigabit Wireless Access – delivering connectivity to residential SFU applications, businesses and MDUs, and Smart Cities.
60GHz V-Band systems are widely utilized in Smart City applications to connect video surveillance cameras where an Ethernet or fiber connection is not available. Cameras are now at least HD, and the industry is heading to 4K and even 8K quality, which is driving camera capacity demands even higher — up to 50 to 100Mbps per camera. Furthermore, public Wi-Fi is witnessing a resurgence in several cities. Because these next-generation outdoor APs are capable of transmitting 1.4 Gbps or more, they require a Gigabit connection. Only 60GHz can support this connection. Point-to-point, point-to-multipoint, and mesh topologies are all powered by the V band. Each has its own set of advantages and disadvantages. New industry standards are being introduced to standardize and expand the use of 60GHz.
60GHz is a relatively uncongested frequency, compared to the lower 2.4GHz and 5GHz frequencies typically used for Wi-Fi networks, which increasingly suffer performance issues owing to high congestion on these frequencies. 60GHz is largely free of these congestion concerns, and as a result promises better signal integrity.
The short wavelength of the 60GHz band is another advantage. This makes it less capable of passing through walls and structures. In the past this has been considered as a disadvantage since the frequency has been viewed primarily through the lens of communications systems, in which we need radio waves that penetrate through walls and buildings. Allowing a signal to penetrate across walls is advantageous in many circumstances. However, with the proliferation of radio signals currently floating through our airways, many users are expressing an increasing desire for signals that remain contained within a fixed space.
Spectrum & Bandwidth
The unlicensed 60GHz frequency has up to 9GHz of spectrum, which is many times more bandwidth than the lesser unlicensed frequencies. This also supports the argument for improved signal integrity at 60GHz.
A number of factors influence whether a signal can pass through a solid object, such as a building's wall. Many of these have to do with the signal's wavelength. The ability of a physical barrier, such as a building's wall, to be pierced by a wireless signal is largely determined by the material used to construct the wall. There are usually no problems with a Wi-Fi signal moving from one room to another in a home as long as the wall isn't composed of a highly conductive metal or an extremely dense substance (brick, concrete, etc.).
The most popular RF and microwave signals, such as AM/FM radio signals, television signals, cellular signals, and Wi-Fi signals, have a reasonably large wavelength, ranging from a few meters to 12 millimeters for Wi-Fi signals. A conventional building wall is effectively "transparent" for signals of this order of wavelength, allowing them to pass through as easily as light passes through glass. Higher frequency signals, on the other hand, cause walls to behave less like light passing through a glass window and more like a closed door.
The Future of mmWave
The future of 60GHz is bright, with the 60GHz mmWave ecosystem growing and spurred by the need for Gigabit connectivity. Many people see a ten-year-old parallel with the 5GHz band, but with an even brighter future. Unlike 5GHz, where RF beams are wide and spectrum is limited, 60GHz has no such restrictions. Congestion and hence interference in the 60GHz mmWave band is nearly impossible now and in the future because RF beams are typically one to five degrees, only span short ranges, and have 14GHz to work with.