All wireless devices have a way to connect to a network in one way or another and WIFI and Cellular technologies are debatably the most accessible ways to get connected. We know that those conduits are there but how they work is much more complicated to explain. MIMO (multiple-in, multiple-out) tech has been around a while in most WIFI and Cellular networks, and now Massive MIMO is taking that tech further in hopes to make the transfer of information more efficient and better performing as we move on to the future of cellular technologies.
MIMO
With antenna tech, there are a few ways of categorizing their capabilities. One way is its ability to transfer and receive signals:
SISO – Single Input Single Output,
SIMO – Single Input Multiple Output,
MISO– Multiple Input Single Output,
MIMO– Multiple Input Multiple Output
Since Cellular signal is based around using MIMO technology, we’ll be talking about MIMO antennas for cellular applications. With MIMO, the base requirements would be to have more than one physical receiving and transferring antenna. This can be as little as a 2X2 but as many as 4X4 antennas on a single array in typical application on a cell tower but in theory there can be many more. Most modern phones are either 2X2 or 4X4 MIMO antenna arrays for typical LTE usage. 5G will be able to push loads of data and MIMO provides the most throughput compared to the other array types, so using MIMO antennas would be the prime way to transfer the most data to as many people as possible.
The way a MIMO antenna itself broadcasts is no different than a SISO antenna would, but a Massive MIMO array is a whole different animal which is why 5G is such a big deal and such a complicated technology to roll out. So, with these hurdles, there will need to be more methods to improve it and that’s where Massive MIMO comes to the table.
Massive MIMO
With 5G still expanding and more devices becoming compatible with 5G, more antennas will be needed to keep up. Massive MIMO will allow that data to get to more people with better performance compared to typical MIMO setups. The current deployments will use 32X32 antenna arrays for 5G! This will require much more power and processing compared to a 4X4 array and this will eventually get to 64X64 arrays to keep up with demand and reliability, but that won’t be the only way signal will be improved. There will be three facets of this technology to improve signal transmission including Spatial Diversity, Spatial Multiplexing, and Beamforming.
Spatial Diversity: Since there are multiple antennas in an array on a tower and signals may reach those antennas at slightly different times based on that distance, those multiple signals can be combined mathematically to improve the quality of the received signal.
Spatial Multiplexing: In the case where those signals are transferred at different times and those signals are of good enough quality, they can be individualized onto separate channels and used to increase throughput and also enabling more users to be supported by a single transmitter.
Beamforming: This technology is already used in WIFI technology and is basically the same for Cellular but on a much wider scale. When multiple antennas are broadcasting in similar directions the signals they broadcast will overlap and inherently create interference and redundant signal that’s wasted. With beamforming, that signal can be combined with certain broadcast techniques to “aim” signal directly towards the device creating a stronger, more powerful, and more efficient signal. Take a look at our “Beamforming” article for more info!
Applications
So, with Massive MIMO now being a mainstay in wireless technology especially with 5G improving and expanding day by day, what are the applications of this new tech? First, what we really care about is speed. With speeds on average of around the 40s in Mbps downloads on normal LTE networks at least, signal is not too slow especially with many people on the network. But with proven 1,000 Mbps (1 Gbps) speeds, many new paths have now been paved for us to expand what we can do with this tech. Latency, or the time it actually takes for signal to be sent and received itself, will be improved as well allowing for live gaming and streaming as well as self-driving automobiles. Range will also be improved especially as beamforming gets better allowing for more reliable connections and better coverage indoors especially high-rise buildings.
The Future of Massive MIMO
With MIMO technology being basically limitless in its expansion there will be a huge shift in how mobile devices will interact and send data to each other. More arrays will be combined, and higher frequencies will be tapped into to get the user even higher speeds that we see today into more people’s hands, homes, and even cars. Hardware in use today will eventually use more advanced software to further expand its capabilities and improve signal as a whole. There will be some growing pains as with each generation of cellular technology, but the pay-offs will be worth the struggle in the long run and Massive MIMO tech will hopefully get us there.
