Optimizing Simultaneous LoS and NLoS Visible Light Communication with Event Cameras
R. van Dijk (TU Delft - Electrical Engineering, Mathematics and Computer Science)
M.A. Zuñiga Zamalloa – Mentor (TU Delft - Electrical Engineering, Mathematics and Computer Science)
Q. Wang – Graduation committee member (TU Delft - Electrical Engineering, Mathematics and Computer Science)
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Abstract
The radio-frequency spectrum is increasingly congested and costly to license, which motivates the use of complementary wireless links in other parts of the electromagnetic spectrum.
Visible Light Communications (VLC) transmits data by modulating visible light.
Among the receiver types used in this field, event cameras are attracting increasing attention due to their significantly higher rates than conventional cameras.
Recent work has studied event-camera VLC in either Line-of-Sight (LoS) or Non-Line-of-Sight (NLoS) settings, but has not combined both links in a single transmitter.
In applications such as infrastructure-to-vehicle communication, receivers may operate under both LoS and NLoS conditions, making it desirable to support both link types simultaneously.
This thesis presents a single LED-matrix transmitter that supports both a high-data-rate (high-fidelity) LoS stream and a low-data-rate (low-fidelity) NLoS stream simultaneously.
To this end, we introduce Dual On-Off Keying (DOOK), a multi-fidelity modulation scheme that encodes high-fidelity data in the spatial and temporal dimensions, while encoding low-fidelity data in the temporal dimension only.
We further combine DOOK with state-of-the-art modulation schemes and design flicker-free variants.
We evaluate the resulting trade-offs between throughput, Bit Error Rate, and flicker.
Using DOOK, we achieve 366 kbps on the LoS link and 2,9 kbps on the NLoS link with a BER below 10-3.
DOOK with Manchester encoding halves the throughput and produces the least flicker among the evaluated schemes.
Compared with prior work, our NLoS throughput is 1,7× higher, while our LoS throughput is 1,8× higher per channel.
More importantly, our system combines both links in a single transmitter.