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Even though I ended up here in southern California, I was originally born in Texas. We have a saying from back there that you may have heard, “everything’s bigger in Texas.” That turned out to be true for me, as I’m the tallest member of my extended family. I’d like to think that the minds behind massive multiple input multiple output (MIMO) antenna arrays were also born in Texas. MIMO has been around for years, but massive MIMO is just starting to gain traction, especially in the 5G arena. 5G promises to bring us blazing speeds and low latency, but in order to do that, it needs to leverage massive MIMO’s unique advantages. These benefits include things like excellent spectral efficiency and great user tracking. With this technology, 5G will become a reality.
What is Massive MIMO?
A lot of people are intimidated when they meet “Texas” head on. For example, when you walk into the Texas state fair and see Big Tex welcoming you in. In the same way, massive MIMO can be a bit much at first. So let’s start with normal MIMO and work our way up to the “massive” scale.
MIMO stands for multiple input multiple output. This means that an antenna array can receive data from and send data to multiple devices at the same time. In order to achieve this, each array uses multiple antennas. With all those antennas and complex signal processing, cell towers can take advantage of various propagation modes to send more data with better reliability.
Massive MIMO is the same concept, just with more antennas. MIMO systems may use around 4 transmitters, where massive MIMO will use more like 100 antennas. The more description is that massive MIMO will use an excessive number of antennas so that transmitters outnumber users. All of those antennas allow massive MIMO to gain even more advantages than current MIMO.
These antennas will become a thing of the past.
Benefits of Massive MIMO
Massive MIMO systems are extremely complex, and implementing them will be harder than riding a bronco in the rodeo. However, the assets that massive MIMO have to offer are worth getting thrown off the horse a few times.
Spectral Efficiency - This is becoming a very important topic as more and more of the electromagnetic spectrum is being used for various communication protocols. Governments have set aside a wide band of frequencies for 5G, but those spectrums aren’t endless. Massive MIMO is able to leverage its array of antennas to focus beams down to individual users. This allows it to achieve spectral efficiencies 10 times better than that of MIMO systems used for 4G.
Energy Efficiency - Texas won’t be producing oil forever, so it’s time to start thinking about energy efficiency for electronic systems as well. In massive MIMO antennas can be used in conjunction to increase the gain of transmitted signals. This means they radiate less power when transmitting data, making for a more energy efficient system.
User Tracking - The same thing that makes massive MIMO energy efficient allows it to accurately track individual users. As the antenna beams are focused to produce high gain, their beam widths decrease. Thus, the tower has to track each user with a narrow signal beam. This tracking will give users a better and more reliable connection than the wide area signals that have been used up to now.
5G will need massive MIMO to efficiently connect billions of devices.
Application to 5G
Massive MIMO sounds kind of cool, like a ten gallon hat. However, I haven’t bought a ten gallon hat, so why would I buy into massive MIMO? The cellular world is really starting to dig into massive MIMO because 5G needs it. There is a limited amount of spectrum available for 5G, so spectral efficiency is very important. 5G networks will also need to connect to billions of devices. For that to happen they’ll need massive MIMO’s pinpoint accuracy and energy efficiency.
The US government recently opened up a new part of the high frequency spectrum for 5G technology. That will be very helpful in the future, but for the short term transition period, frequencies below 6 GHz will provide a smoother transition from 4G/LTE. It just so happens that massive MIMO operates best at frequencies below 6 GHz. This band is already crowded, so the extra spectral efficiency makes massive MIMO a prime candidate.
As technology advances our world is becoming more connected. The Internet of Things is taking off, self driving cars are on the horizon, and there are already networks in place for smart cities. 5G is poised to move into all of these arenas, and will need to connect billions of devices. In order to do that it will need massive MIMO to be able to beam data to and from individual devices. Massive MIMO’s energy efficiency will also mean that these networks won’t require another oil boom to power them.
Massive MIMO is a technology that’s almost as exciting as a rodeo. Almost. Using huge numbers of antennas will allow cell networks to connect large numbers of users efficiently and reliably. Those attributes also happen to be what’s needed in order to implement 5G. With billions of devices coming online and a limited frequency spectrum, 5G will need massive MIMO to help us transition into the future.
5G is coming, and if you’re not already designing PCBs for it, you might want to start. CircuitStudio can help you with that. It has a wide range of excellent features that will help you design the next generation of communication PCBs.
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