Conserving spectrum via Massive MIMO in the next age of connectivity.

by Sriram Rajagopal | Head of Systems & Firmware

5G technology will enable a new world of devices that can “think” and communicate instantaneously -- Imagine trillions of devices coordinating among themselves, such as smartphones, drones, robots, autonomous vehicles, scanners, and sensors. Such a large population will inevitably lead to traffic, causing airwaves to become heavily congested and contended.

In fact, spectrum will become such a precious resource that its use and reuse will be an area of focus. To achieve higher capacity, spectral efficiency must be improved. This is How to Conserve Spectrum via Massive MIMO 2 where multi-user MIMO (multiple input, multiple output) and large-scale antenna systems come in. Massive MIMO is the umbrella concept that embraces all the tricks (spatial diversity, spatial multiplexing, 3D beamforming, interference reduction, link budget improvements) that improve performance and coverage that support the true 5G experience. By improving spectral efficiency in 5G technology, we can enable a wider range of devices, achieve higher capacity, and reduce interference.

Sending pointed beams simultaneously toward specific users can help cover a large user base. To achieve this, beamforming can be used where a stream of data for different users is sent simultaneously over a larger number of antennas, or even to multiple specific client devices. Think of it like everyone gets their own spotlight instead of sharing a large light together. However, this requires several critical components, including measuring the channel from the antennas to each and every user using sounding reference signals, generating digital beams to these users, and critically pairing these users to achieve improved spectral efficiency. These are achieved with disaggregated solutions and an open-defined interface.

These components can be arranged in numerous combinations to optimize the coverage of real deployments, which can be expensive to tweak in the field. However, they must be validated beforehand. Key considerations for massive MIMO can be distilled down to 3 critical areas: (1) Large antenna systems, (2) Sound reference signals, and (3) User pairing. And one needs an emulator that can simulate the massive MIMO user environment.

To see all this live, EdgeQ has developed a software-defined, Massive MIMO Open RAN Solution with 32 simulated beams used across two users each doing 4x4, achieving a total maximum of 8 layers at a power footprint of <50 Watts. This accomplishment represents the world’s first instantiation of a 5G ORAN infrastructure solution based on a standard server, an inline acceleration, a Radio Unit (RU) system, and a third-party L2/L3 software stack from collaborating companies. For an encore of our invited keynote on this topic at the Keysight World India 2023, click here.