Block Markov Superposition Transmission with Color Shift Keying

Color shift keying (CSK) is the only Multiple-input multiple-output (MIMO) modulation scheme supported by IEEE 802.15.7 standard. It modulates the intensity of visible lights emitted by colored Lightemitting-diodes (LEDs) for data transmission. We discuss different demodulation criteria for CSK in either signal space or color space, and compare their Bit-error rate (BER) performance. In order to improve the performance of CSK, we present a coded CSK modulation scheme, which is based on the recently proposed coding scheme called Block Markov superposition transmission (BMST). For comparison, we consider Reed-Solomon (RS) code together with CSK (referred as RS-CSK), which is exploited in PHY Ⅲ operation mode in IEEE 802.15.7 standard. The mutual information of CSK is also given for performance analysis. Simulation results show that the proposed scheme achieves a significant gain compared with the RS-CSK.