MISO Wireless Optical Communication Under a First-Moment and a Peak-Power Constraint: Theoretical and Practical Aspects

This paper studies the multiple-input single-output free-space optical intensity channel with signal-independent additive Gaussian noise and subject to both an average- and a peak-intensity constraint. Closed-form expressions for the asymptotic high-signal-to-noise-ratio (high-SNR) capacity and for the corresponding capacity-achieving input distribution are presented. Moreover, several practical modulation schemes are proposed that approach the capacity over a wide range of practical SNR values.