Comparison of CAP and OFDM Modulation for LED-based Underwater Optical Wireless Communications

This paper presents an experimental demonstration of carrierless amplitude and phase (CAP) and orthogonal frequency division multiplexing (OFDM) modulation in underwater optical wireless communications (UOWC). The performance of CAP is then compared to that of OFDM. Here, the CAP is implemented with decision feedback equalizer (DFE) and Volterra series based DFE, both of them employ the recursive least square (RLS) algorithm. The error performance of CAP is evaluated for modulation orders of 16 and 64 and compared with that of OFDM in an LED-based UOWC link.