Measured Distributed vs Co-located Massive MIMO in Industry 4.0 Environments

Massive multiple-input multiple-output (MIMO), the cornerstone of 5G, is in theory well understood, but many parts of the practical challenge remain unclear, e.g. what antenna configuration is suitable for which scenario. Inheriting from the over-provisioning of antennas and thus the possibility of creating an ultra-reliable wireless link, Massive MIMO is also intended for industrial scenarios. In these environments, a large number of reflectors, movements, and distortions are to be expected, which results in a high variation of fading and propagation delay. We show that in the case of distributed antennas these channel outages through fading/blockage are minimized Comparing this case to the standard co-located approach, the link-reliability is increased by more than 3 dB for the same amount of antennas. This is verified in two different, yet typical, future factory environments by using standard channel parameters. Through these measurements we show that the requirement of perfectly syncing the distributed antenna arrays can be relaxed, still achieving reasonable gains.