Most wireless communication networks are constructed using the unlicensed 2.4 GHz and 5 GHz radio frequency bands. These frequency bands are limited by the data transfer rates they can provide. However, some wireless network applications use a very high-frequency band (60 GHz) that can offer Gigabit data transfer rates.
60 Ghz frequency is a part of the V-Band frequencies in the US. It also falls under the category of millimetre radio (mmWave) bands. Millimetre wave radios use frequencies that range anywhere from 30 GHz to 300 GHz.
Millimetre wave radios are named so because their wavelengths range from 10 millimetres to 1 millimetre. 60 GHz has gained momentum in commercial applications. Until recently, this frequency was used primarily for military communication.
Characteristics of 60 GHz frequency
License-free 60GHz radios have unique features that offer many operational advantages and set them apart from the traditional low-frequency radios. Some of these are:
License-Free large spectrum
Federal Communications Commission (FCC) allocated a 7 GHz of un-channelized spectrum for license-free operation between 57 GHz – 64 GHz.
This is in contrast to 0.5 GHz of spectrum allocated in 2.4GHz and 5GHz frequency bands for WiFi bands. A large spectrum makes it possible for multi-gigabit RF (Radio Frequency) links, allowing channels of roughly 2 GHz each.
Narrow Beam Antennas
60GHz radios have very narrow beams associated with them. This enables coexistence of multiple 60 GHz antennas even if all antennas operate at same transmit and receive frequencies.
These radios can easily be isolated based on small lateral or angular separations. One can also use cross-polarized antennas to distinguish two radio waves. In antenna theory, polarization refers to the orientation of the radio beam.
Cross polarization means that the two radio beams are orthogonal to each other.
Easy to Install and Align
Even though the radio beam for 60GHz frequency is much narrower than other radio signals, it is still wide enough that a non-expert installer can set it up using simple visual alignment tools.
Further, the beam signals are also easy to align and do no tilt easily.
Oxygen Absorption and Security
The 60 GHz spectrum has a unique property. Oxygen is known to attenuate 60GHz radio signals. This does limit the distance that the frequency can cover but at the same time offers advantages regarding security and lower interference when compared to other wireless technology.
Drawbacks of 60 GHz
Each technology comes with its pros and cons. In addition to numerous advantages that 60 GHz is associated with, it also comes with several disadvantages.
When compared with 5GHz radio signals (predominantly used for WiFi), transmission at 60 GHz has a much smaller range when transmitted at the same power.
This is because when the electromagnetic waves move through the air, there is a loss of signal. This loss is higher for higher frequencies. As mentioned above, 60GHz band comes with a unique property of oxygen
absorption. This absorption gets much pronounced at a distance beyond 100 meters.
As the frequency of radio waves increase, its capacity to penetrate walls and other obstructive objects decreases. WiFi signals using 2.4 GHz frequency band can penetrate walls much easily than 5 GHz frequency band while 60 GHz transmission struggle badly when it comes to penetrating obstructions.
Protocols for 60GHz wireless transmissions
WirelssHD, also known as UltraGig, WirelessHD is the first standard 60 GHz protocol which was developed to support high-definition video streaming. This is a proprietary standard owned by a company called Silicon Image (known initially as SiBeam).
The first version of the protocol (WirelessHD 1.0, released in 2008) supported data rates up to 4 Gbps. The revised version (WirelessHD 1.1) improved data transfer rate to 28 Gbps (maximum).
WiGig stands for Wireless Gigabit Alliance which is a trade association that developed standards for high-speed wireless transmission using 60 GHz frequency. The first version of the protocol (WiGig 1.0) was published in May 2010 which supported data transfer rates of up to 7Gbps.
In 2013, the alliance was subsumed by Wi-Fi Alliance. WiGig is also known as 802.11ad standard. In addition to high-speed video streaming, WiGig is also being used as a wireless replacement for cables.
An example of this would be connecting video monitors and other peripherals wirelessly using WiGig.
WiGig and WirelessHD are competing for technology for the commercial use of the technology. Efforts are being made to solve range limitation issues associated with the frequency.
It is also expected that protocols like WiGig might even replace Wi-Fi technology in future.