ACM in 60 GHz Wireless: Automatic Coding and Modulation

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.


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.

Modern 60GHz V-band MMW Wireless Communications with ACM (Adaptive Coding and Modulation)

A modern 60GHz V-band radio featuring ACM

ACM in real-world 60GHz links

ACM technology in 60GHz MMW V-band 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):

V-Band 60GHz Rain Attenuation and planning

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.

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60GHz Wireless: The IEEE 802.11ad standard

IEEE 802.11ad wireless safety

IEEE802.11ad was the first 60GHz V-band Wi-Fi standard. Offering high speeds this standard takes WiFi speed to level far higher than previous WiFi standards. 802.11ad Wi-Fi is rated for data throughput up to 4,600Mbps, or four times faster than the comparable 5GHz band 802.11ac.

What is 802.11ad?

IEEE 802.11ad is an amendment to the IEEE 802.11 wireless networking standard, developed to provide a Multiple Gigabit Wireless System (MGWS) standard at 60 GHz frequency

CableFree 802.11ad 60GHz V-band Wireless Network

After revision, the 60 GHz band covers the frequency of 57 to 71 GHz . The frequency band is subdivided into 6 (previously 4) different channels in IEEE 802.11ad, each of them occupy 2160 MHz of space and provide 1760 MHz of bandwidth

802.11ad channels:

ChannelCenter (GHz)Min. (GHz)Max. (GHz)BW (GHz)

Note: Some of these frequencies might not available for the use of IEEE 802.11ad networks around the world (reserved for other purposes or requires licenses).

How does 802.11ad Wi-Fi work?

Like previous versions of Wi-Fi, 802.11ad is an official standard ratified by the Wi-Fi Alliance. Unlike previous versions, however, the tech behind it didn’t come from the IEEE (Institute of Electrical and Electronics Engineers). Instead, it’s based on tech created by the WiGig (Wireless Gigabit) Alliance, which was officially announced back in 2009, entered draft stage with the IEEE in 2011, and finally emerged as the standard it is today when the WiGig Alliance merged with Wi-Fi Alliance in 2013.

Limitations of 802.11ad

Because it uses the V band of millimeter wave (mmW) frequency, the range of IEEE 802.11ad communication would be rather limited (just a few meters and difficult to pass through obstacles/walls) compared to other conventional Wi-Fi systems. However, the high frequency allows it to use more bandwidth which in turn enables the transmission of data at high data rates up to multiple gigabits per second, enabling usage scenarios like transmission of uncompressed UHD video over the wireless network.

The Next Generation

The following standard for even higher capacity in 60GHz V-band is IEEE 802.11ay

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