Adaptation to the LEDs flicker requirement in visible light communication systems through CE-OFDM signals

• Published in: Optics communications 2019-06, Vol.441, p.14-20
• Main Authors: vd Zwaag, Klaas M., Neves, José L.C., Rocha, Helder R.O., Segatto, Marcelo E.V., Silva, Jair A.L.
• Format: Article
• Language: English
• Subjects: Constant envelope signals; Flicker adaptation; Orthogonal frequency division multiplexing; Peak-to-average power ratio; Visible light communications
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2019.02.017

Constant-envelope OFDM signals based on electrical phase modulation are proposed in visible light communication (VLC) systems to adapt to the LEDs flicker requirements. Experimental results demonstrate that this peak-to-average power ratio (PAPR) reduction technique thoroughly adapts to the flicker requirements in line-of-sight single-input single-output (SISO) VLC channels, at a cost of performance penalties, as indicated by the numerical evaluations provided in this paper. The performance of a 272.87 Mb/s CE-OFDM system, with 64-QAM subcarrier mapping in a bandwidth of 100 MHz, is compared with the performance of a conventional OFDM system, after propagation through SISO and multiple-input single-output (MISO) VLC channel models. Besides the strong dependence on the phase modulation index 2πh, the simulation results show that, in the SISO scenario, the CE-OFDM technique introduces performance penalties. However, with 2πh=1.3, the phase modulation based scheme outperforms traditional OFDM systems in the MISO architecture, due to the transmission of low PAPR signals.