Massive MIMO is a technology where tens or even hundreds of antennas are used alongside technologies like beamforming to give a very large capacity gain to an area. It is most commonly deployed with TDD on high frequencies like 2600MHz. In the case of Vodafone, 2600MHz TDD is used (Band 38) and is currently known to be deployed on Vodafone in Manchester, Bristol, Newbury, Glasgow and Cardiff using Huawei AAU5271.
Three Huawei Massive MIMO panels are used on Manchester University although two are visible on these pictures. The GPS antennas used for time sync can be seen also. The site also has 4G on 2600MHz, 2100MHz (15) and 800MHz.
In the left image, the Band 38 is operating in TM3, so not in Massive MIMO. This will be because the load is low. In the middle example, TM7 is present and the antenna is operating as Massive MIMO. The Right image shows the performance of the FDD LTE.
Vodafone 5G Massive MIMO
For Vodafone 5G Massive MIMO, please see Vodafone UK 5G Masts: Huawei, Ericsson and O2 Host 5G
Detailed page about Cardiff's masts, please see Cardiff Mobile Phone Masts
Map showing Massive MIMO installations
For Mast maps, please refer to the "Location Mast Galleries" on the main menu.