Ergodic capacity comparison of optical wireless communications using adaptive transmissions.

TitleErgodic capacity comparison of optical wireless communications using adaptive transmissions.
Publication TypeJournal Article
Year of Publication2013
AuthorsHassan MZ, Hossain MJ, Cheng J
JournalOptics express
Volume21
Issue17
Pagination20346-62
Date Published2013 Aug 26
Abstract

Ergodic capacity is investigated for the optical wireless communications employing subcarrier intensity modulation with direct detection, and coherent systems with and without polarization multiplexing over the Gamma-Gamma turbulence channels. We consider three different adaptive transmission schemes: (i) variable-power, variable-rate adaptive transmission, (ii) complete channel inversion with fixed rate, and (iii) truncated channel inversion with fixed rate. For the considered systems, highly accurate series expressions for ergodic capacity are derived using a series expansion of the modified Bessel function and the Mellin transformation of the Gamma-Gamma random variable. Our asymptotic analysis reveals that the high SNR ergodic capacities of coherent, subcarrier intensity modulated, and polarization multiplexing systems gain 0.33 bits/s/Hz, 0.66 bits/s/Hz, and 0.66 bits/s/Hz respectively with 1 dB increase of average transmitted optical power. Numerical results indicate that a polarization control error less than 10° has little influence on the capacity performance of polarization multiplexing systems.

DOI10.1109/EMBC.2013.6611204
Alternate JournalOpt Express