What is Massive MIMO And How it Paves the Way for 5G Adoption?

An insurmountable number of devices, be it your smartphone, VR headset, or the security cameras outside your house, are connecting to telecom networks at all once. This adds up to a rapid increase in data traffic over time, with improvements in bandwidth becoming the need of the hour. What we all need are high data speeds, isn’t it? As Chinese telecom giant Huawei predicts, the year 2021 will witness a seven-fold increase in global mobile data traffic as compared to 2016. It has further added that data demands for an individual will reach an average 15GB per month in the next five years. We are still witnessing the advent of 4G LTE networks in countries like India, but telecom operators across the globe have started experimenting with even more complex and robust technologies to maximize signal strength, user capacity, and data speeds. They’re using a smart antenna technology called Massive MIMO (Multiple Input, Multiple Output) that will form the basis for our fifth-generation (5G) cellular technology. It is still in nascent stages of development but is soon expected to gain prominence. So, if you have been wondering what is massive MIMO, here’s everything you need to know about massive MIMO:

What is Massive MIMO and its relation to 5G?

Massive MIMO (Multiple Input, Multiple Output), also known as Large-Scale Antenna Systems, is the backbone for the evolution of wireless communication. The MIMO technology is expected to prove immensely beneficial for supporting more mobile users, providing faster speeds and more reliable network services in the long run.

Currently, most 4G LTE network infrastructures only enable the placement of 8 antennas (transmitter + receiver) at the base station, which is not proving enough to accommodate the growing needs of mobile users. This provides a limited bandwidth, affecting data speed and number of users who can connect to this station.

This is where MIMO steps in and allows you to use two or more transmitters and receivers simultaneously to exchange data over the same radio channel. The technology has already been implemented in some advanced 4G network stations in the form of 4 x 4 MIMO and is currently being explored by a few operators in India as well.

Massive MIMO antenna system
Massive MIMO antenna system prototype (Image courtesy: National Instruments)

But, expanding the said concept to accommodate close to 100 antennas in a single array at the base station (cellular tower) is what will form the basis for upcoming 5G networks. The increase in the total number of antennas adds up to more transmitters/receivers at a place, leading to an increase in possible signal paths and better performance in terms of both the data speeds and link reliability. Massive MIMO can induce up to four times improvement in speeds and several times more expansion of network capacity.

The collection of antenna systems in a Massive MIMO network do not form exact balloon-like beams seen in most previous and current network systems. Instead, the orthogonal nature of the signals emitted by the collection of antennas form individual beams, catering to one or more mobile station (the users) at an instant. Since Massive MIMO makes use of numerous complex technologies, the simplest way to explain the functioning of its antenna system is through the diagram attached underneath.

5G setup
Evolution of a 4G network into 5G MAssive MIMO network (Image Courtesy: Mitsubshi)

This means it enables the operators can serve a larger set of mobile devices in an area by deploying the Massive MIMO technology. And the same is further scalable as operators can add even more antennas to the current setup to increase possible signal paths and improve efficiency without hampering the existing spectrum.

Benefits of Massive MIMO over Current 4G Networks

Since a larger number of input and output antennas are used in the Massive MIMO (5G) system, it will help telecom operators largely improve the coverage and data speeds. This will be made possible due to high spectral and energy efficiency, which increases due to a large multiplexing, as well as antenna array gain combined. Here are the primary benefits of Massive MIMO (M-MIMO) antenna systems over current 4G systems:

1. Improved Coverage and Higher Speeds

Thanks to the use of Massive MIMO technology, possibly combined with higher frequency spectrums, the telecom companies will be able to cater to the needs of a larger variety of devices in the future. Not only this, the signal strength indoors would be extremely strong and off the charts.

The beam-forming capabilities of Massive MIMO systems will enable telecom operators to rapidly spread high-speed coverage to rural areas as well. A direct line of sight works well with higher frequencies, thus, providing even greater speeds.

The primary aim of an upgrade is also to increase the data speed and experts are expecting minimum speeds of 1 Gbps, reaching up to 10 Gbps. This has already been proven in some experiments with Gigabit LTE demos shown by Chinese networking giant ZTE at CES earlier this year.

2. Low Infrastructure and Component Costs

Since most global telecom giants are steadily upgrading their infrastructure to now support high-speed 4G networks (with pre-5G speeds), the complete upgradation to 5G would be a smooth ride. The existing 4G systems are already employing MIMO techniques which are to be scaled when a plausible 5G technology comes to fruition.

The new Massive MIMO antenna systems will not only have a large number of antennas but it’ll also be scalable. It will be easier for telecom giants to add new antennas to this system to append existing speeds and user base. Also, the large number of antennas will result in the formation of a robust network, which won’t be affected by an individual failure in their antenna system.

3. Support for Time-constricted Connections

While Massive MIMO-enabled 5G networks provide an enhanced coverage and data speed, it reduces the time taken for the signals to travel between the transmitter and receiver. This is known as latency and upcoming 5G networks will help reduce the same to further facilitate the use of these networks for VR/AR, self-driving, and other AI or ML-controlled services.

mixed reality

Challenges in Massive MIMO Antenna Deployment

While researchers have been experimenting with Massive MIMO antenna tests for the past few years, the systems that have made it to the market still have lesser antennas than the telecom companies desires for the advent of 5G networks. This is due to the limitations we have encountered in the implementation of the technology. Here are the challenges being faced in their widespread deployment:

1. Signal Processing Complexity

This is one of the most prominent difficulties being encountered in setting up the Massive MIMO base stations. The increased number of antennas and the frequencies at a singular location leads to increased chances of interference. This issue can, however, be solved by the adoption of a wider spectrum and zero-fault precision technology which will slash the inter-site channel interference. While the large number of antennas will add to complexity across the board, it makes the network even more resistant to failures. 

2. Limited Spectrum Availability

As you may have already heard, the distribution of a frequency spectrum is controlled by the governing body and telecom operators need to place bids in order to secure a section of that particular spectrum.

Now, the basic problem lies in the fact that the 3GHz spectrum prevalent in current times is already cluttered due to the overload of new data connections. And it is proving challenging to utilize higher frequency millimeter waves (3 GHz – 300 GHz) to build Massive MIMO base stations as the waves don’t penetrate solid materials and absorbed by trees or rain clouds.

mmwave 5G
Frequency Spectrum (Image Courtesy: UT Austin)

But, technology giants and telecom operators are working hand-in-hand to increase signal gain by making multiple antennas (MIMO) concentrate radio signals in a narrow directional beam without increasing their transmission power. Samsung R&D and Huawei have tasted success in the experiments, but these narrow beams are extremely sensitive to alignment changes.

Ongoing Research and Deployment of Massive MIMO Networks

The aforementioned network system is not a prototype but has already been implemented at a smaller scale in the existing 4G scenario. Huawei has been working with local telecom operators such as China Mobile and Japan’s SoftBank for over a couple years to experiment its Massive MIMO setups commercially.

After rigorous experimentation, SoftBank has now been named the very telecom operator to debut its commercial Massive MIMO network towards the end of 2016. Other operators such as China Mobile, Vodafone, and T-Mobile have also started rolling out this technology to a limited set of its users across their respective countries.

If the biggest question nagging at the back of your mind is, Will our current smartphones be compatible with these Massive MIMO networks? Then, the straightforward answer is mostly yes. A large number of existing devices can take advantage of 4G MIMO networks, providing Gigabit speeds without any hiccups.

First-ever 5G-capable Deployments in India

While numerous global telecom players, in conjunction with hardware giants, have already experimented with Massive MIMO on their networks, India has just recently also joined the 5G futuristic drive with the deployment of its first such network.

The country’s leading telecom giant, Airtel, made headlines when it announced that it has become the one to achieve this feat. The rollout of India’s first M-MIMO (Massive Multiple-Input Multiple-Output technology has been kicked off with Bengaluru and Kolkata. The trial is, however, expected to expand to other parts of the country in the coming months.

Airtel has deployed the new 5G technology as part of their ongoing network transformation program called Project Leap. It expects the Massive MIMO technology to improve existing network capacity seven-fold while using the same spectrum it already owns. It believes the same is even going to provide two times better speeds on their existing 4G deployment.

In addition, Chinese networking giant ZTE has announced that it is partaking in the pre-5G Massive MIMO experiments in collaboration with widely known operators such as Vodafone and Reliance Jio. Whereas Huawei is the face behind Airtel’s deployment in the country, as said in an official statement.

If viewed from the perspective of the current state of the telecom industry in India, this is an attempt on these telecom giant’s parts to maintain a stronghold in the country. They’ve been recently woken with a surprising jolt by their fiercest new competitor, i.e Reliance Jio, who has now managed to trample them with its 4G LTE network rollout within a year.

Expected Widespread Rollout

Most reports released by networking giants like Ericsson or Nokia currently suggest that 5G network technology will witness a breakthrough and reach the masses by the 2020s. This is not a rigid timeline but falls in line with the operating pattern of the industry, which sees an upgraded technology being debuted within a decade.

technology rollout timeline
Image Courtesy: Sam churchill/Flickr

The 3G network technology was first debuted back in October 2001, whereas 4G LTE saw widespread adoption after a decade around 2011. Thus, it is possible to speculate that the ongoing Massive MIMO efforts will come to fruition by the end of this decade. One can see pre-5G implementations of the technology, both on the consumer and operator-end in the next couple of years. The crowd at 2018 Winter Olympics could be the very first to witness the said innovation, followed by the FIFA 2018 World Cup. Even chipmaker Qualcomm has stated that it plans to roll out 5G-compatible (Gigabit) devices along a similar timeline.

We may have witnessed a prolonged rollout of 4G LTE services in India, something which is still under process. But, the country’s telecom behemoths no longer want to drag behind in the race to adopt latest technologies because of the looming competition and consolidation within the country itself.

SEE ALSO: What is Bluetooth Mesh Networking and How It Works

Massive MIMO: A Technological Race for 5G Adoption

A bird’s-eye view of Massive MIMO developments also shows that India is further building on its transformative image of being a technological powerhouse. The government is now undertaking the required steps to kick-start the evolution of cellular technology.

The government has already set up a high-level forum to evaluate the current scenario and approve actions plans for the timely rollout of 5G services. It has allocated a massive ₹500 crore corpus for 5G research and development purposes, which puts us on the global map, alongside the countries leading the adoption of such technological advancements. There is no true “5G” network defined at the moment and we’ll have to be on the lookout for the same in the coming years.

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