5G new radio (NR) is conceived to provide new service types, namely, enhanced mobile broadband (eMBB), ultra-reliable and low latency communications (URLLC), and massive machine-type communications (mMTC).
Among these, eMBB is expected to provide exceptionally fast data speeds to facilitate services that have high throughput requirements such as high definition (HD) video streaming, virtual reality (VR), and augmented reality (AR). The goal of eMBB is not just to serve faster transmission speeds when a user is near a base station, but also to deliver unparalleled end-user experiences in crowded areas such as airports or sports stadiums, thus allowing users to enjoy seamless high-quality streaming services, regardless of their locations.
What is a massive MIMO (mMIMO)?
Massive multi-input multi-output (MIMO) is a significant breakthrough technology that improves the capacity and user experience of 5G eMBB. Instead of broadcasting data throughout the entire coverage area, the massive MIMO system concentrates the signal energy to a specific user, resulting in significant improvement of throughput and efficiency.
This characteristic not only increases the downlink (DL) and uplink (UL) signal strength but also enhances the cell throughput by allocating multiple beams to one or multiple users. The spatially optimized signal can minimize its interference toward other users and/or adjacent cells and reduces interference levels of the entire network, especially in interference-limited cell deployments.
Why massive MIMO (mMIMO)?
During this time, when 5G RAN equipment is being deployed, massive MIMO technology comes into the limelight for the following reasons:
- Many newly deployed 5G systems operate on higher frequency (TDD) bands than 4G. In order to make up for increased path loss of high frequency and limited coverage of TDD, coverage enhancement techniques are essential for 5G cell deployment.
- According to many recent reports, mobile traffic demand is expected to grow at an explosive rate. Newly deployed 5G equipment should be capable of high system capacity and end-user throughput.
- 5G system does not have many legacy mobiles that limit the gain of advanced MIMO approaches. Hence, state-of-the-art MIMO technologies are easily introduced in 5G systems and can achieve performance improvement.
The benefit of ‘Massive’ Antennas
- Coverage enhancement and shaping.
- Improved single-user throughput.
- Cell throughput gain by spatial division multiple access.