National Instruments and Scotland's University of Edinburgh are partnering on a test bed to improve indoor wireless communications capacity using spatial modulation techniques combined with visible light communications to create what are being called high-density optical attocell networks.
The idea of using light fidelity, or Li-Fi, to complement capacity-challenged Wi-Fi and cellular networks has been touted by a number of industry visionaries, including Harald Haas, chair of mobile communications at the University of Edinburgh. Now Haas contends that combining Li-Fi with spatial modulation will harness massive MIMO gains in both the optical and RF domains for energy-efficient indoor wireless communications
"We've known for a long time that decreasing cell size can significantly increase cellular capacity and user data rates, but it's not been clear how we could facilitate that given current spectrum, energy and interference limitations," said Haas. "RF wireless and optical wireless networks that work together using spatial modulation and massive MIMO approaches could allow us to effectively mitigate interference and significantly increase energy efficiency, coverage and capacity using existing infrastructure."
Haas' Edinburgh team will use National Instruments' LabView reconfigurable I/O (RIO) architecture for rapid prototyping. LabView RIO is part of National Instruments' graphical system design platform. It combines the open LabView graphical programming environment with commercial off-the-shelf (COTS) hardware to simplify development. National Instruments says this results in "higher-quality designs with the ability to incorporate custom design."
Using the company's FlexRIO software defined radio Bundle with reconfigurable FPGAs and interchangeable I/O adapter modules, the Edinburgh team is building prototypes that operate beyond the rates of a commercial RF wireless system. The team recently achieved 3.5 Gbit/s from a single color LED.
In addition, Haas and Professor Cheng-Xiang Wang, head of the Advanced Wireless Technologies Lab at Heriot-Watt University, have already used National Instruments' PXI Express hardware and LabView system design software to create a working prototype showing spatial modulation techniques over a wireless RF channel.
"We are excited to collaborate with Professor Haas, who has been pioneering visible light communications and spatial modulation for nearly a decade," said Erik Luther, wireless c communications group manager at National Instruments. "Through the LabView RIO architecture, Haas can rapidly prototype a first-of-its-kind wireless test bed."
- see this joint release
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