5 things you need to know about MU-MIMO

October 3, 2019 at 8:00 AM


When you’ve got multiple devices using the same network, multi-user MIMO (MU-MIMO) is the way to go. MU-MIMO enables numerous Wi-Fi devices to receive multiple data streams at the same time. This is exceptionally more efficient than the single-user MIMO used by many routers. Here, we’ll take a look at the top 5 things you need to know about MU-MIMO.


1.      One-Way or Two-Way


Whether MU-MIMO is one-way or two-way depends on the Wi-Fi standard being used. MU-MIMO utilizes the 80211ac standard, which works solely with downlink wireless connections. Simultaneously sending data to multiple users is something that only wireless routers and APs are able to do. When the individual wireless devices are sending data to that router or AP, they have to take turns or separately use SU-MIMO to send multiple streams when it’s their turn. That said, multiple wireless devices will be able to receive data and be able to utilize simultaneous streams for sending data when 802.11ax Wave 2 comes into play.


2.      OFDMA Takes It Up a Notch


Orthogonal Frequency-Division Multiple Access (OFDMA) technology is part of 802.11ax and separates the channels into smaller segments so multiple devices can communicate at the same time. This technology compliments the capabilities of MU-MIMO. It organizes how the channels are used by allowing each device their own channel so they can coordinate when to talk more easily. While it is similar to MU-MIMO, OFDMA offers a different set of capabilities as it can be used in high density environments with low throughput or small-packet applications like IoT sensors.


3.      802.11ax (aka Wi-Fi 6) = Concurrent MU-MIMO Streams


The introduction of 802.11ax into the mix increases the number of users in a MU-MIMO group from four to eight. The ability to have more devices connected at the same time can improve throughput and make connections faster.


4.      2.4 GHz & 5 GHz are both Options


802.11n and 802.11ac limited MU-MIMO to the 5 GHz bandwidth, but with 802.11ax, MU-MIMO will now be able to use both the 2.4 & 5 GHz bands. While 2.4 GHz can only handle a maximum of three, small, legacy channels at one time, this improvement could allow faster speeds in the often overcrowded 2.4 GHz band.


5.      Benefits of Beamforming


MU-MIMO takes advantage of another feature of 802.11ac and 802.11ax, beamforming. This keeps signals from dispersing randomly in different directions by pointing it to the intended wireless devices. This, in turn, improves Wi-Fi speeds and ranges by using the signal more proficiently.


There you have it, five more reasons why MU-MIMO can be a game changer for your wireless network. To read more about MU-MIMO, check out more of our blog posts.


RF Frequencies 101

February 1, 2018 at 8:00 AM


RF, radio frequency, is an electromagnetic wave between 1 MHz and 3 GHz used in wireless networks to transmit video, voice and data. They can also be used for AM radio broadcasting, navigational beacons and shortwave radio. Waves from 3 GHz to 30 GHz are microwave frequencies used for FM radio, aviation communications, radar and satellite links. Millimeter wave frequencies range from 30 GHz to 300 GHz and are used to transmit large amounts of data and simultaneous voice or video. RF waves can be transmitted through different media such as coaxial cable, a circuit board or through an antenna.


There are three main factors to consider for RF waves: frequency, wavelength and Hertz. Frequency is the number of electromagnetic wave cycles that pass a specific point per unit of time. Wavelength is the distance after which the electromagnetic wave fields repeat themselves. Hertz is a measurement of the wave cycles per second.


           1 Hertz (Hz)              =      1 wave/ 1 second

                                           1 Kilohertz (kHz)        =      1 thousand waves/ 1 second

                                           1 Megahertz (MHz)     =      1 million waves/ 1 second

                                           1 Gigahertz (GHz)      =      1 billion waves/ 1 second


To get the full picture, and for a handy reference, here is a chart of RF frequencies:



For more information on RF frequencies used in wireless networks, check out some of our other blog posts: RF Antenna FAQs and Wireless Infrastructure 101.


Cliffs Notes: Industrial Wireless Network Frequencies

September 8, 2016 at 8:00 AM


Today’s industrial wireless networks use multiple frequencies in order to support a variety of applications. In a single industrial setting there may be two, three or more frequencies being used since each offers unique capabilities.


If you’re trying to decide which frequency would be best for your industrial wireless application, we’re here to help. We’re going old school with a CliffsNotes-style review to sum it all up for you.




There are three ISM wireless frequency bands: 900 MHz, 2.4 GHz and 5 GHz. The most popular frequencies used in industrial networks are the 900 MHz and 2.4 GHz bands. Many industrial facilities have such diversified needs and processes that their wireless network uses multiple frequencies. For example, let’s say there’s an oil refinery using a remote monitoring system, a security system and high speed Wi-Fi in the central control office – this situation may require the use of all three frequency bands.


Facilities such as oil refineries, wastewater treatment plants and manufacturing operations may have wireless systems that utilize lower bandwidth communications. Simpler tasks like opening a valve or relaying temperature readings from a tank require less bandwidth. In this instance, the 900 MHz frequency band is often used because it allows for longer distance, more reliable transmissions and better penetration of obstructions. This frequency is ideal when remote monitoring of facilities requires a longer reach.


These facilities may also use video security systems which are very common in industrial installations. Most security systems use IP cameras which can be wired with cables or may be connected via wireless links. Wireless IP camera networks require higher bandwidth to send video and/or audio. In this case, 2.4 GHz Wi-Fi networks are the best bet. Using an 802.11g/n network provides security systems the speed they need with transmission rates of up to 300 Mbps.


5 GHz is not as commonly used as the 900 MHz and 2.4 GHz frequencies in industrial networks. It has the shortest range but offers very high bandwidth which can be overkill for many industrial communication applications.  Often 5 GHz systems are used as a backhaul link to connect two 2.4 GHz systems.


Study Guide


Here is a handy chart to give you an overview of the ISM band frequencies and how they are used in industrial wireless networks:


No matter which frequency best suits your needs, L-com has all of the products to build your industrial wireless network including antennas, amplifiers, splitters/filters and access points


For more information on industrial wireless networks, check out our blog post 5 Things You Need To Know About Industrial Wireless.


Comments on this post? Other topics you’d like us to cover? Email us at engineeringhub@l-com.com


Wireless Frequencies: The CliffsNotes Version

April 28, 2016 at 8:00 AM


Wireless antennas operate at different frequencies to best suit different wireless applications.  In order for the system to work properly, the antenna frequency must match the frequency of the amplifier, access point or router to which it will be attached.

If you’re trying to decipher what each wireless frequency does and/or which one would be best for your wireless application, we’re here to help. We’re taking you back to school and in true CliffsNotes-style we’ll sum it all up in an easy to read package. 




The cast of characters is simple: 900 MHz, 2.4 GHz and 5 GHz frequency bands.


The FCC has allocated these three frequencies for unlicensed Industrial, Scientific and Medical (ISM) applications. Because they don’t require licensing, these frequencies have played a pivotal role in the growth of the wireless industry.

In the US, the 900 MHz, 2.4 GHz and 5 GHz wireless frequency bands are used for consumer and commercial Wi-Fi and WLAN applications, as well as commercial Radio Frequency Identification (RFID) and Supervisory Control and Data Acquisition (SCADA) applications. 


Study Guide


Each frequency band has a different purpose and its own set of characteristics – some good, some bad. Here is a handy chart to give you an overview of each frequency.



Now you should be able to choose the best frequency for your wireless application and you’re sure to pass any pop-quiz on wireless frequencies - you can even print out this chart and tape it inside your Trapper Keeper.


For a detailed look at the frequency allocations of entire radio spectrum, download the United States Frequency Allocations Chart.


Pros and Cons of the ISM Band Frequencies

November 26, 2015 at 8:00 AM


900, 2,400, 5,000 – these are not factors in an algebraic algorithm.  These are the unlicensed frequency bands that have helped propel the growth of the wireless industry.


In the US, the 900, 2,400 and 5,000 MHz frequency bands are set aside by the FCC for unlicensed Industrial, Scientific and Medical (ISM) applications. Each ISM band frequency is allocated for a different purpose. They are used for consumer and commercial Wi-Fi and WLAN applications as well as commercial Radio Frequency Identification (RFID) and Supervisory Control and Data Acquisition (SCADA) applications.


Here, we take a closer look at the pros and cons of each frequency.


900 MHz

What the 900 MHz band lacks in bandwidth, it makes up for in distance. This frequency is very narrow which limits its maximum data rates, though it is able to penetrate obstructions such as tree and leaves in the Line-of-Sight (LOS).


The 900 MHz band is commonly used by applications such as SCADA and RFID which have lower data rate requirements than applications found in the 2.4-5 GHz frequency bands. The type of data packet usually sent in these applications is a simple on/off command to a motor or a valve, for instance.


The 900 MHz frequency surpasses other bandwidths with its ability to penetrate obstructions such as trees and leaves in the Line-of-Sight.  For example, the 2.4 GHz band is absorbed by water found in trees and leaves which causes path loss of the transmission. Thus, 900 MHz is often used for Non-Line-Of-Sight (NLOS) applications.


2.4 GHz

2.4 GHz is the frequency of choice for the home user and commercial businesses. It is the primary band used for cordless phones, microwave ovens, baby monitors, Wi-Fi, Bluetooth, printers, keyboards and gaming controller applications. Voice, video and data communications are typically used in 2.4 GHz systems requiring higher data rates of up to 300 Mbps for 802.11n applications.


As the most widely used frequency, the 2 .4 GHz band can become overcrowded. When excessive overcrowding occurs, Wi-Fi network signal may be weak or not work at all. In some cases, it's best to connect 2.4 GHz Wi-Fi networks using backhaul links on the less crowded 5 GHz frequency.


5 GHz

The 5 GHz frequency is often used in commercial Wi-Fi applications. It is also the frequency used for the emerging 802.11ac standard which will provide up to 1.3 Gbps of wireless data throughput.  802.11n can also use the 5 GHz frequency. On the flip side, this super-speed band has the shortest range of all three ISM frequency options.


There you have it, the good and the bad of each ISM frequency.  Now you know all the factors to consider when choosing the best band for your application.




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