On the Implementation of Carrierless Amplitude and Phase Modulation in Visible Light Communication

OAPA Carrierless amplitude and phase modulation (CAP) is one of the spectrally efficient schemes that has been proposed to tackle the limited modulation bandwidth challenge in visible light communication (VLC). The VLC technology leverages existing lighting fixtures to provide wireless data communication, which makes it attractive for many applications. However, the commercially available white LEDs that are predominantly employed in VLC offer low modulation bandwidths that limit the achievable data rate. Thus, CAP modulation is employed to improve achievable data rate, primarily due to its implementation simplicity and high spectral efficiency. The CAP scheme also has a special feature in that it can be implemented as a single band or a multiband scheme which provides design flexibility. This paper presents an in-depth study of the implementation of CAP in LED-based VLC systems, highlighting the unique features that make it specially suited for VLC applications. Furthermore, a comprehensive investigation is carried out regarding the design parameters of the CAP modulation transceiver, its benefits and techniques to mitigate the challenges of CAP-based VLC systems

Joint equalization and synchronization for carrierless amplitude and phase modulation in visible light communication

\ua9 2017 IEEE. In this paper, a linear adaptive least mean square (LMS) fractionally spaced equalizer (FSE) is proposed to jointly mitigate the severe inter-symbol interference (ISI) and timing jitter encountered by carrierless amplitude and phase modulation (CAP) in visible light communication (VLC) systems. The performance of FSE is compared to that of its counterpart, the symbol spaced equalizer (SSE), at the forward error control (FEC) bit error rate (BER) limit. It is shown that at a signal-to-noise ratio (SNR) of 20 dB and FEC BER limit of 3 7 10-3, FSE is able to achieve a bit rate of 95 Mb/s (spectral efficiency η of 14.6 bits/s/Hz) while only 30 Mb/s (η of 4.6 bits/s/Hz) is possible with SSE using CAP-64. It is observed that the FSE performance is insensitive to timing jitter while SSE performance suffers severe degradation. The results therefore indicate that FSE is better suited for CAP-based VLC systems than the widely used SSE