ACM is a key technology in 60GHz V-band wireless technology: Automatic Coding and Modulation ensures High speed links offer high Availability at long range and in high rainfall.
Introduction
Adaptive Coding and Modulation (ACM) or Link adaptation is a term used in wireless communications to describe the matching of the modulation, coding and other signal and protocol parameters to the conditions on the radio link. Reasons why ACM is an advantage include:
The pathloss
Interference due to signals coming from other transmitters
Sensitivity of the receiver
Available transmitter power margin
Long range/distance
Rainfall in high rain regions
Modern 60GHz radios use a rate adaptation algorithm that adapts the modulation and coding scheme (MCS) according to the quality of the radio channel, and thus the bit rate and robustness of data transmission. The process of link adaptation is a dynamic one and the signal and protocol parameters change as the radio link conditions change.
A modern 60GHz V-band radio featuring ACM
ACM in real-world 60GHz links
ACM technology in 60GHz MMW V-band Links
Why ACM is important: O2 and 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.
ACM Summary
Our modern 60GHz radios feature the latest technologies to ensure reliable, mission-critical links in all conditions. We offer Planning Tools to predict throughput, availability and performance before deployment
Please contact our team to find out more about 60GHz V-band Radios.
Choose CableFree for V-band 60GHz MMW radios: CableFree V-band MMW radios are ideal for dense urban areas: Reliable 1Gbps P2P & P2MP for Backhaul, Campus, Metro Network & Safe City CCTV.
Watch the video below introducing the range of radios
Introducing CableFree V-band 60GHz radios
CableFree: Secure, Fast & dependable
CableFree V-band MMW uses latest generation technology to ensure your networks are secure, fast & dependable
Choose CableFree for high speed networks
A wide range of V-band radios including Point to Point, Point-to-Multipoint, Sector, CPE & Mesh Base Station Products
Features and Benefits for Metro Networks
Rugged and Reliable Carrier-grade design
1Gbps full duplex capacity
Point to Point and Point to Multipoint configurations are supported
Base Stations with 10GBE ports for up to 4Gbps full duplex aggregate capacity
High Gain radio units for long distance point to point links as well as larger Point to Multipoint networks
Compact, low-cost CPE units for remote sites with low visual impact
Advanced security features: includes optional encryption, Access Control Lists (ACL), secure IPSEC tunnels and other features to create ultra secure urban wireless networks
Multicast Filtering support for CCTV applications to prevent “flooding” of your network with multicast traffic from cameras
Builds on our 24 year heritage in design and supply of reliable, mission critical wireless networks
Manufactured in the UK in our ISO-9001 certified facility
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.
Summary
CableFree V-band 60GHz radios are ideal for building modern, urban wireless networks
Use CableFree to Build modern Wireless Metro Networks using V-band 60GHz MMW radios:
CableFree 60GHz V-band MMW radios are ideal for dense urban metro areas: CableFree Millimeter Wave Radios are ideal and reliable 1Gbps P2P & P2MP for 4G & 5G Backhaul, Campus, Metro Network & Safe City CCTV & Smart City Applications.
CableFree V-band 60GHz MMW tech is secure, fast & dependable
Features and Benefits for Metro Networks
Rugged and Reliable Carrier-grade design
1Gbps full duplex capacity
Point to Point and Point to Multipoint configurations are supported
Base Stations with 10GBE ports for up to 4Gbps full duplex aggregate capacity
High Gain radio units for long distance point to point links as well as larger Point to Multipoint networks
Compact, low-cost CPE units for remote sites with low visual impact
Advanced security features: includes optional encryption, Access Control Lists (ACL), secure IPSEC tunnels and other features to create ultra secure urban wireless networks
Multicast Filtering support for CCTV applications to prevent “flooding” of your network with multicast traffic from cameras
Builds on our 24 year heritage in design and supply of reliable, mission critical wireless networks
Manufactured in the UK in our ISO-9001 certified facility
Summary
CableFree V-band 60GHz radios are ideal for building modern, urban wireless networks
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 –
Regulation of V-band (60 GHz) varies globally. Check regional regulation before planning a V-band 60GHz network. Key regulation includes EC (Europe) & FCC (USA). Note that within Europe, individual member states may have different interpretation of rules.
V-band Summary
The V-band ostensibly ranges from the 41 GHz to the 75 GHz band. Parts of that band of spectrum are used for millimeter wave radar and various scientific applications. The 60 GHz band has been attracting considerable interest recently. Compared to only 70 MHz spectrum available in the 2.4 GHz band and 500 MHz in the 5GHz band for Wi-Fi, there is 7 GHz available in 60 GHz V-band. They are well suited to high-capacity, short-hop (<2 km) communications with narrow beams. The Wi- Fi 802.11ad low-power, very short-range devices will operate in the 60 GHz band, potentially offering data throughputs of up to 10 Gbps
V-Band 60GHz Spectrum
EC 60 GHz Rule Change
In late 2013, the European Commission (EC) issued a decision, the 2013/752/EU, that made a number of amendments to a prior policy document (2006/771/ EC). The main objective of the revised policy document is to constrain transmission power levels to ensure they do not interfere with other wireless equipment. In the case of the short-range devices operating in the 57 GHz to 66 GHz band, they are restricted to 40 dBm Equivalent Isotropically Radiated Power (EIRP) and 13 dBm/MHz EIRP densities. Fixed outdoor installations are excluded from complying with these restrictions. Furthermore, it will ensure that these short-range devices do not become a serious source of interference for backhaul links in the 57 GHz to 64 GHz band.
FCC 60 GHz Rule Change
In late 2013, the FCC voted unanimously to change the rules governing the 60 GHz unlicensed band and said that the new raised power levels would improve the use of unlicensed spectrum for high- capacity, short range outdoor backhaul, which is particularly useful for small cells. There are several reasons why this rule change was important for small cell backhaul. In the 60 GHz band, wireless transmissions are attenuated by oxygen absorption and moisture or “rain fade,” which limits their range; also, the signal will not penetrate foliage or buildings, requiring a clear LoS. At this high frequency, the antenna is a small dish that matches the small form factor of the small cell and can be installed unobtrusively outdoors.
The FCC raised the power limit for outdoor links operating in the 57 GHz to 64 GHz band on an unlicensed basis. The EIRP limit was raised from 40 dBm (equivalent to 10 Watts) to a maximum of 82 dBm (158,489 Watts), depending on how high the antenna gain is. The new power limit is comparable to others the FCC has in the fixed microwave services.
The FCC believes this will support higher-capacity outdoor links, such as small cells, extending to about 1 mile (1.6 km). The FCC also eliminated the need for outdoor 60 GHz devices to transmit an identifier. Indoor 60 GHz devices (for example, those based on WiGig’s 802.11ad standard) are still constrained to the much lower power limitations, which prevents interference with outdoor fixed link devices.
Europe
In Europe, the European Telecommunication Standards Institute ( ETSI) and the European Conference of Postal and Telecommunication ( CEPT ) adopted some general recommendations for operation of devices in the 57-66 GHz band. The CEPT recommendation REC (09)01, which was supplemented by ETSI EN 302 217 harmonised standard, calls for a maximum EIRP power level of +55 dBmi, but typically limits maximum conducted power to +10 dBm and the minimum antenna gain to +30dBi. This approach does not allow the trade-off of Executive Summary 1 Regulatory Background antenna gain and power in the way that the more flexible U.S. standard does.
United Kingdom (UK)
In 2010 the UK Office of Communications (OFCOM) approved the unlicensed use of the 57…64 GHz spectrum. Although the spectrum allocation follows the FCC standard (maximum EIRP of +55 dBm), the maximum conducted power of +10 dBm and the +30 dBi minimum antenna gain is modelled after the European ETSI standard”
60GHz (V-Band) is now becoming a popular frequency band in wireless world, with both short-range and wider area applications ahead for the tiny beams of this unlicensed millimeter radio technology.
The frequency — part of the V-Band frequencies — is considered among the millimeter radio (mmWave) bands. Millimeter wave radios operate using frequencies from 30GHz to 300GHz. Until recently, 60GHz has typically been used for military communications as well as some commercial applications.
Major technology vendors show growing interest in the technology and the associated patents. Qualcomm Inc. (Nasdaq: QCOM) bought Wilocity recently to combine 60GHz WiGig technology with WiFi. Google (Nasdaq: GOOG) bought Alpental, a startup that, according to one of its founders, is using 60GHz to develop a “hyper scalable mmWave networking solution for dense urban nextGen 5G & WiFi.”
Why 60GHz, and why now? Here are a few reasons the market is expanding:
Drivers
WiGig:
A short-range wireless specification — using the Institute of Electrical and Electronics Engineers Inc. (IEEE) 802.11ad specification — that can link devices at up to 7 Gbit/s over a distance of up to 12 meters. That’s 10 times faster than the current 802.11n WiFi, though with less range. This makes the technology ideal for wirelessly delivering high-definition video in the home. The Wi-Fi Alliance has WiGig-certified products which started to arrive in 2015.
Wireless backhaul:
Particularly for small cells, operators can use the 60GHz radios to connect small cells to a fiber hub. (See More Startups Target Small-Cell Backhaul.)
Wireless bridges:
These are useful for providing extra capacity at events, ad-hoc networks, and private high-speed enterprise links.
Wireless Video:
Wireless video: Some startups have jumped the gun on the WiGig standard and plowed ahead with their own 60GHz video connectivity using the Sony-backed WirelessHD standard.
Point to Point, Point to Multipoint & Mesh Networks
60GHz is ideal for Point to Point (P2P, PTP) links as well as Point to Multipoint (P2MP, PTMP) and also Wireless Mesh Networks.
Why 60GHz?
A global unlicensed band exists at 57-64GHz. It is largely uncongested compared to the 2.5GHz and 5GHz public bands currently used for WiFi.
There’s also a lot of it. “The 60 GHz band boasts a wide spectrum of up to 9GHz that is typically divided into channels of roughly 2GHz each,” Intel Corp. (Nasdaq: INTC)’s LL Yang wrote in an article on the prospects for the wide-area and short-range use of the technology. Spectrum availability is “unmatched” by any of the lower-frequency bands.
The spectrum is now open and approved for use across much of the world. This includes the US, Europe, and much of Asia, including China.
As we’ve already seen, 60GHz technology is expected to offer blazing wireless transmission speeds.
Issues with 60GHz
No technology is ever perfect, right?
Transmissions at 60GHz have less range for a given transmit power than 5GHz WiFi, because of path loss as the electromagnetic wave moves through the air, and 60GHz transmissions can struggle to penetrate walls. There is also a substantial RF oxygen absorption peak in the 60GHz band, which gets more pronounced at ranges beyond 100 meters, as Agilent notes in a paper on the technology. Using a high-gain adaptive antenna array can help make up for some of these issues with using 60GHz for wider area applications.
Some vendors have also argued that there are potential advantages for the technology over omnidirectional systems. “The combined effects of O2 absorption and narrow beam spread result in high security, high frequency re-use, and low interference for 60GHz links,” one vendor notes
