Massive Expectations for Massive MIMO

Ever growing data consumption is a major challenge for mobile network operators. While more and more consumers are transferring more and more data, higher data speeds required for good quality video streaming and advanced online applications are becoming harder to achieve.

Radio frequency spectrum is a scarce and often expensive resource, and along with cellular equipment sites, they certainly are the most important assets to the mobile network operators. Using these assets as efficiently as possible enables mobile network operators to deliver better service and experience to their customers.

Traditionally, the industry’s standard response to capacity demand is to introduce new technologies and new frequency bands. While 5G promises higher data rates, lower response times and higher capacity, it also requires mobile network operators to invest in new network infrastructure and acquire new, potentially expensive spectrum. Furthermore, consumers will need to upgrade their mobile phones to new models. In other words, the whole ecosystem needs to be uplifted to reap the benefits of 5G, and that can take several years. However, 5G includes technologies such as Massive MIMO, that can be used to solve today’s needs for enhancing the cellular network capacity and improving the mobile user experience. While there is no consensus definition of a Massive MIMO antenna, it is commonly understood to have multiple independently controlled antenna elements that can form beams concentrating the radio energy to a desired location. Users in that location receive higher quality radio signals and experience higher data rates. Additionally, unwanted radio energy or interference is also minimized. Overall the network capacity increases without adding new expensive frequency spectrum.

The expectation in the industry is that Massive MIMO should improve the capacity at least two to three times and more when multi-user MIMO becomes widely available. In addition to double or triple capacity, the cell edge performance is expected to improve significantly. This is important for video streaming and advanced applications requiring high data rates no matter how near or far the mobile users are from the cell towers.

While delivering on the performance expectations, Massive MIMO must meet several additional requirements to be attractive as a commercially viable solution for mobile network operators today:

  • Support existing devices. In order to maximize the returns, every user needs to benefit from Massive MIMO without having to purchase a new handset. The solution cannot rely on slowly refreshing device fleet which is largely beyond mobile network operator’s control.

 

  • Address FDD frequency bands. Over 85% of mobile networks are built on using FDD frequency bands. While low bands, below 1 GHz, provide for large coverage area, most of the traffic is carried in mid-bands, from 1700 MHz to 2600 MHz. Using Massive MIMO on these bands gives the greatest immediate capacity and performance gains.

 

  • Multi-band support. Many mobile network operators hold multiple mid-bands, such as AWS and PCS in North America, and therefore, ideally, any Massive MIMO solution should support at least two bands simultaneously. Incorporating a passive low band antenna within the same enclosure will further optimize the use of site real estate.

 

  • Compatible with existing infrastructure. Massive MIMO should be a simple retrofit to the existing network infrastructure. It should not drive front-haul upgrades nor require additional baseband processing capacity. It should also be software upgradeable to support future 5G.

In addition to the above challenges, Massive MIMO is perceived to be expensive and not suitable for network wide deployments because of unmanaged interference. Blue Danube’s Massive MIMO features an innovative array architecture and uses machine learning techniques to manage network interference making it not only cost effective, but also widely deployable while still meeting the above requirements.

It is obviously not easy to meet the performance expectations and deployment requirements, otherwise we would have seen more commercially viable Massive MIMO solutions in the market already, wouldn’t we?

 



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