Subcarrier Intensity Modulated Optical Wireless Communications Using Noncoherent and Differentially Coherent Modulations

Error rate performance is analyzed for subcarrier noncoherent and differentially coherent modulated optical wireless communication systems over atmospheric turbulence channels. Both Gamma-Gamma and negative exponential channels are considered. Using a moment generating function approach, we obtain a unified bit-error rate expression for a family of noncoherent and differentially coherent modulations. We also analyze the symbol-error rate performance of subcarrier M-ary differential phase-shift keying and M -ary noncoherent frequency-shift keying modulated systems using the same frequency domain approach. Our asymptotic analysis reveals relative error rate performance of M -ary differential phase-shift keying and M-ary noncoherent frequency-shift keying in different channel conditions.