60GHz V-band wireless has many advantages, which are explained in our article below: High speed links, lack of interference, all whilst using the safest and environmentally sound technology:
Introduction
In 2001, the Federal Communications Commission (FCC) set aside a continuous block of 7
gigahertz (GHz) of spectrum between 57 and 64 GHz for wireless communications. A major factor in this allocation with commercial ramifications is that the spectrum is “unlicensed” – in other words, an operator does not have to buy a license from the FCC before operating
equipment in that spectrum. The licensing process typically is very expensive and time consuming. Up until then, less than 0.3 GHz of bandwidth had been made available at lower frequency bands for unlicensed communications.
60GHz V-Band and the Electromagnetic Spectrum
The 57-64 GHz band is located in the millimeter-wave portion of the electromagnetic spectrum, where the wavelength varies from ten millimeters (30 GHz) down to one millimeter (300 GHz).
The millimeter-wave portion of the RF spectrum has been largely unexploited for commercial wireless applications. That is now changing. 60GHz-Wireless has used its well-established expertise in millimeter-wave products and technologies to develop wireless products operating in that spectrum that enable two-way wireless communications at data rates that previously could only be accomplished with fiber optic cable.
In addition to the high-data rates that can be accomplished in this spectrum, energy propagation in the 60 GHz band has unique characteristics that make possible many other benefits such as excellent immunity to interference, high security, and frequency re-use. In this paper, we will discuss in detail the benefits of wireless communications in the 57 to 64 GHz band.
Oxygen Absorption of 60GHz
Point-to-point wireless systems operating at 60 GHz have been used for many years by the
intelligence community for high security communications and by the military for satellite-to-satellite communications. Their interest in this frequency band stems from a phenomenon of nature: the oxygen molecule (O2) absorbs electromagnetic energy at 60 GHz like a piece of food in a microwave oven. This absorption occurs to a much higher degree at 60 GHz than at lower frequencies typically used for wireless communications. This absorption weakens (attenuates) 60 GHz signals over distance, so that signals cannot travel far beyond their intended recipient. For this reason, 60 GHz is an excellent choice for covert satellite-to-satellite communications because the earth’s atmosphere acts like a shield preventing earth-based eavesdropping. Because of the rich legacy of applications in this band, a wide variety of components and subassemblies for 60 GHz products are available today.
Dense frequency re-use of 60GHz signals
Another consequence of O2 absorption is that radiation from one particular 60 GHz radio link is quickly reduced to a level that will not interfere with other 60 GHz links operating in the same geographic vicinity. This reduction enables higher “frequency reuse” – the ability for more 60GHz links to operate in the same geographic area than links with longer ranges. As an example, let’s compare two different links, one operating near 60 GHz and the other at a frequency that is less affected by O2 absorption. The second link could be operating at another unlicensed frequency such as 2.4 GHz or 24 GHz. Consider a typical operating scenario where both links are operating over a distance of one kilometer with the transmitter’s power output adjusted such that the signal level at the receiver is 30 decibels (dB) above the background noise. Consequently, more 60 GHz links can be used in the same area without worrying about interference. Also, the 60 GHz links are far more secure given their limited range.
Highly Directional Antennas: Advantages of spectrum re-use and security
Directivity is a measure of how well an antenna focuses its energy in an intended direction.
Point-to-point radios should have highly directional antennas as the goal is to connect to end points of a link. Ideally, all the transmitted energy is directed just at the intended recipient. Highly focused antennas minimize the possibility of interference between links in the same geographic area, minimize the risk that the transmission will be intercepted, and maximize performance.
Operating at higher frequencies inherently results in a more focused antenna. Antenna directivity is limited by the physical principle of diffraction that states that the beam width is inversely proportional to the operating frequency. Therefore at 60 GHz, the beam width is far narrower than at the lower frequency unlicensed bands.
Beamforming
Modern V-band radios such as our own offer sophisticated Beamforming to ensure solid, reliable links and ability to mount on flexible structures such as street lamp poles, monopoles and other street furniture or available structures.
O2 versus Rainfall Planning
60GHz wireless link planning has to take account both O2 absorption as well as rainfall. Link distances of millimeter-wave radios operating in the real world are limited primarily by rain. Users of these products typically want the links to provide robust communication capability, such as the “five nines” of availability demanded by most carriers. In this application, the rainfall rates where the product is used will typically be more of a limiting factor than O2 absorption
60 GHz radio links are engineered to overcome the effects of rain attenuation. To simplify, the maximum operating link distance is a function of level of availability desired (for example, 99.999% or 99.99%) and rainfall rates in the geographic area of intended use. Again to simplify, link distance increases as level of availability and rainfall rates decrease. Rainfall statistics are so well known for locations around the globe that range and availability can be accurately predicted. The following chart shows the attenuation due to rain (solid line) compared to O2 absorption (dashed line):
In moderate rain regions, the rain attenuation is about twice the oxygen attenuation, and in heavy rain regions, the rain attenuation is more than three times the oxygen attenuation. Therefore, in designing a 60 GHz link to provide robust communication capability in the real world, rain attenuation is a larger factor than oxygen absorption.
So, this combination of oxygen absorption and robust engineering enables 60 GHz links to provide the best of both worlds. The oxygen absorption limits the distance of a ransmission in providing for security and frequency re-use even in the best weather. Engineering for rain attenuation enables carrier-class service even in the worst weather conditions.
Safety of 60GHz V-band
Is 60GHz Safe to use? YES – these 60GHz radios use only 10mW transmit power, only 1/20 the power of a standard cellphone, and are mounted in outdoor areas away from people. Please see this page for details and to learn more about safety of wireless systems.
Conclusions: Advantages of 60GHz V-Band
The 60 GHz band is an excellent choice for high-speed Internet, data, and voice communications offering many key benefits and advantages:
- Unlicensed operation – no need to spend significant time and money to obtain a license from FCC or other regional regulator (note: not in all countries)
- Highly secure operation – resulting from short transmission distances due to oxygen absorption and narrow antenna beam width
- Virtually interference-free operation – resulting from short transmission distances due to oxygen absorption, narrow antenna beam width, and limited use of 60 GHz spectrum
- High level of frequency re-use enabled – communication needs of multiple customers within a small geographic region can be satisfied
- Fiber optic data transmission speeds possible – 7 GHz of continuous bandwidth available compared to <0.3 GHz at the other unlicensed bands
- Mature technology – long history of this spectrum being used for secure communications
- Carrier-class communication links enabled – 60 GHz links can be engineered to deliver “five nines” of availability if desired
Please do contact our team to find out more about 60GHz V-band Radios –
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