  Visible Light Communication (VLC) is seen as a complementary wireless
technology to Radio Frequency (RF). However, VLC is very sensitive to the
signal blockage and suffers from shadowing due to the high directionality of
the optical channel. Hence there is a big interest in researching novel
approaches for VLC like usage of multiple antenna techniques providing spatial
diversity which can be exploited as a way to combat signal blockage and fading.
We present a complete and low-cost MIMO-VLC transceiver system consisting of
COTS components. In particular, we show that COTS 802.11n (WiFi) devices can be
used so that the physical and data link layers of RF WiFi are reused for VLC.
In addition, this allows us to directly utilize the multiple antenna (spatial)
techniques available in 802.11n. Results from our measurement study show that
such techniques are highly effective at improving the robustness of VLC links
in the presence of obstacles and node mobility. Moreover, we show that multiple
antennas can also be used to increase the data rate of VLC by means of spatial
multiplexing.
