Dynamic range constrained clipping in visible light OFDM systems with brightness control

Visible light communication (VLC) systems can provide illumination and communication simultaneously by way of light emitting diodes (LEDs). The communication function is achieved by employing simple and low-cost intensity modulation and direct detection (IM/DD) schemes. Brightness control and flicker mitigation are two main challenges for the illumination function. Orthogonal frequency division multiplexing (OFDM) has been considered for VLC for its ability to boost data rates. However, OFDM waveforms have high peak-to-average power ratio, and will be clipped if its magnitude is beyond the dynamic range of LEDs. Clipping can cause the performance degradation of communication as well as illumination. In this paper, we will propose an iterative clipping method considering brightness control and flicker mitigation. We will investigate the performance in terms of error vector magnitude (EVM) as well as computational complexity. We will formulate the EVM minimization problem as a convex optimization problem to compare with the iterative clipping method.

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