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Bristol boffins blast 1.59 Gbps down ONE 20 MHz channel
MIMO with 128 antennas cranks wireless speeds up very nicely
VIDEO In what's being touted as a “5G breakthrough”, University of Bristol researchers have demonstrated that MIMO (multi-in, multi-out) antenna arrangements can be scaled up to more than 100 transmitters.
The demonstration, as described in a canned statement, used 128 antennas transmitting to as many as 12 single-antenna clients simultaneously.
That allowed the same 20 MHz of spectrum (in the 3.5 GHz band) to achieve an aggregate 1.59 Gbps (a bit over 130 Mbps per client), a spectrum efficiency of 79.4 bits/Hertz.
The project is part of the European Union's MAMMOET “massive MIMO” development effort. The EU is keen to drive 5G development, as a counterbalance to heavy Korean and Chinese investment in the sector.
MIMO is already heavily used in systems like 802.11n and 802.11ac to improve spectrum efficiency. The multiple antennas – usually four in current systems – create different spatial paths a signal can follow, each of which can be modulated with a different data stream.
For example, in a typical household, a Wi-Fi has plenty of walls to bounce off, creating the different paths between antennas and the receiver. Signal processing at the receiver handles the business of distinguishing the different streams.
Hence scaling that up to 128 paths demands serious signal processing, carried out by four FPGAs in the Bristol demonstration.
The university used six USRP transceivers from Ettus Research at the client end, with two laptops connected to each.
National Instruments and the University of Lund also took part in putting the demonstration together. ®
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