Comparison of SNR and Peak-SNR (PSNR) as performance measures and signals for peak-limited two-dimensional (2D) pixelated optical wireless communication

Two-dimensional (2D) pixelated Optical-Wireless-Communication-Systems (OWCS), with Intensity-Modulation, Direct-Detection (IM/DD), commonly use computer-display (on transmit-side), and camera (on receive-side). One-dimensional (1D) IM/DD OWCS and channels, which use discrete optical components, are average-power-limited, due to eye-safety rules. In contrast, 2D pixelated-channels are peak-power limited. However, in the literature, both 1D and 2D systems-evaluations, use the average-power SNR, as a signal to noise (SNR) measure. We first show an example of a signal which has better SER vs. SNR performance, but worse actual result for a given channel conditions. We further show that the Peak-power Signal-to-Noise-Ratio (PSNR), which is a common image quality evaluation measure, is a better metric, used in SER vs. PSNR. We further define and optimize a signal for maximum variance, given a peak-limited-channel, under PSNR; we conclude with such signal-example, showing superior-performance when-compared to known 2D modulation method.