Symbol-level Precoding for Multiuser Visible Light Communication

Visible light communication (VLC) is a promising technique for future high speed wireless networks due to its advantages including high data rate and spectral efficiency. For practical multiuser VLC systems, there are severe interferences between different users. To mitigate the interference, a novel symbol-level precoding scheme that utilizes the constructive interference is investigated to enhance the transmission performance. Numerical results show that the scheme outperforms the conventional schemes, whilst the simulated bit error rate (BER) with the scheme agrees well with the analytical solution. Moreover, an experiment is conducted to verify its effectiveness in an VLC system with 2 LEDs and 2 users. Experimental results show that the communication radius with the symbol-level precoding scheme can be improved by approximately 0.1m and 0.2m compared with ZF precoding and no precoding, respectively.