Performance of Color Shift Keying under Non-Linear System Model and Illumination Constraints

The IEEE 802.15.7 standard defines specifications for short-range optical wireless communication (OWC) using visible light. The standard specifies color shift keying (CSK) as the preferred modulation scheme for indoor OWC while simultaneously providing illumination. In light of illumination requirements, human eye´s optical perception introduces unique non-linearities in the CSK signaling chain. It is shown that these non-linearities introduce performance penalties of more than 15 dB, 10 dB, and 5 dB for M = 4, 8, and 16 CSK respectively. A new metric called luminous- signal to-noise ratio (LSNR) is also introduced to fairly compare performance of any two OWC signaling schemes operating at a user defined illumination intensity level and is used to compare performance of M-ary CSK implemented with different colored sources. Within the same context, and at a target bit error rate of ≤ 10^-3, simulation results indicate that clipping negative receiver output signal does not have an impact on M-ary CSK performance.