Duobinary Modulation for Visible Light Communications

The paper proposes and experimentally investigates the performance of the duobinary transmission technique for a highly bandlimited VLC system. By adding a controlled amount of inter-symbol interference (ISI) into the transmit pulse shaping filters, the supported data rate can be doubled requiring the same signal bandwidth. To gain full insight into duobinary signalling, the so-called modified binary scheme is also tested. The bit error rate (BER) performance of both systems is measured for a range of data rates, before comparison with the ideal binary and traditional on-off keying non-return to zero (OOK-NRZ) formats across the same physical link. We show the duobinary system can support higher bit rates and lower BER than OOK-NRZ while requiring half the bandwidth of the binary scheme