Last year, the 128-antenna Massive MIMO testbed at University of Bristol was used to set world records in per-cell spectral efficiency. Those measurements were conducted in a controlled indoor environment, but demonstrated that the theoretical gains of the technology are also practically achievable—at least in simple propagation scenarios.
The Bristol team has now worked with British Telecom and conducted trials at their site in Adastral Park, Suffolk, in more demanding user scenarios. In the indoor exhibition hall trial, 24 user streams were multiplexed over a 20 MHz bandwidth, resulting in a sum rate of 2 Gbit/s or a spectral efficiency of 100 bit/s/Hz/cell.
Several outdoor experiments were also conducted, which included user mobility. We are looking forward to see more details on these experiments, but in the meantime one can have a look at the following video:
Update: We have corrected the bandwidth number in this post.
I have been investigating 3GPP release 15 for a while. As I seen, number of proposals, discussion on Full-Dimension MIMO with feedback CSI outnumber TDD Massive MIMO. So I am doubt about possibility of adopting TDD Massive MIMO for release 15. Can you explain that? thank you
Not all features need to be specified in the standard. I believe that feedback procedures are usually standardized, so that the UE and eNodeB know what information that will be interchanged. However, reciprocity-based precoding in TDD requires no feedback and thus can be implemented at the base station without the UE knowing exactly which algorithms are being used. Read the post “Massive MIMO Trials in LTE Networks” for some details on this.