A team of 5G engineers from the Universities of Bristol and Lund, National Instruments (NI) and BT has started trials of next generation mobile phone technology.

The trials take place in a large indoor hall at BT Labs in Adastral Park, Suffolk, that mimics a stadium environment, as well as outdoor trials on the Adastral Park campus.

“Massive MIMO has the potential to significantly boost available data rates in future 5G mobile networks”

 

The aim is to test massive antenna systems called MIMO and improve the understanding of massive MIMO radio channels under mobile conditions with untethered devices. While carrying out these field experiments, the team found that the technology could offer spectrum efficiency figures in excess of the 100 bits/s/Hz mark, ten times better than today’s 4G systems.

“Massive MIMO is a key technology for 5G and the research team’s achievements last year with massive MIMO arrays, which are cellular base stations with more than 100 antennas, demonstrates that this technology could deliver ultra-fast data rates to high densities of smartphones and tablets,” says Mark Beach, Professor of Radio Systems Engineering in the Department of Electrical and Electronic Engineering and Manager of Bristol’s EPSRC Centre for Doctoral Training in Communications (pictured right).

The research team of five PhD students from the CDT and a researcher from Lund University worked with the BT research team, led by Ian Mings, to assess the performance of a 128 element Massive MIMO system operating at 3.5 GHz at BT’s Adastral Park campus.

An un-tethered world first

Initial experiments took place in BT’s large exhibition hall and used 12 streams in a single 20MHz channel to show the real-time transmission and simultaneous reception of ten unique video streams. The system also supports simultaneous transmission of 24 user streams using 64QAM encoding on the same radio channel with all modems synchronising over-the-air. It is believed that this is the first time such an experiment has been conducted with truly un-tethered devices, from which the team were able to infer a spectrum efficiency of just less than 100bit/s/Hz and a of 2 Gbits/s in the single 20MHz wide channel.

“BT Labs is excited to once again be at the forefront of mobile technology development”

 

In addition to the indoor trials, a series of outdoor experiments were conducted with the array at a height of around 20 metres. This enabled far field array characterisation, multi-element handset performance as well as experiments to improve the understanding of the massive MIMO radio channel under mobile conditions to be carried out.

“The BT Labs have a long history of pioneering wireless research, and with the acquisition of EE [in Bristol], we’re excited to once again be at the forefront of mobile technology development,” said Professor Tim Whitley, Managing Director of Research and Innovation at BT. “Massive MIMO has the potential to significantly boost available data rates in future 5G mobile networks, and we’re pleased to be able to explore that potential with leading academics in the field at the University of Bristol.”

The experimental system uses a flexible software defined radio (SDR) system from NI combined with equipment from smart city testbed Bristol is Open.

The researchers are now processing the data sets and aim to publish their findings in leading journals in the near future as well as adding enhancements to the system in preparation for further trials.

More details on the EPSRC Centre for Doctoral Training in Communications are here.