The University of Bristol continues to be one of the driving forces in demonstrating reciprocity-based Massive MIMO in time-division duplex. The two videos below are from an outdoor demo that was carried out in Bristol in March 2018. A 128-antenna testbed with a rectangular array of 4 rows and 32 single-polarized antennas per row were used. The demo was carried out with a carrier frequency of 3.5 GHz and featured spatial multiplexing of video streaming to 12 users.
Prof. Mark Beach, who is leading the effort, believes that Massive MIMO in sub-6 GHz bands will be the key technology for serving the users in hotspots and sport arenas. Interestingly, Prof. Beach is also an author of one of the first paper on multiuser MIMO from 1990: “The performance enhancement of multibeam adaptive base-station antennas for cellular land mobile radio systems“.