Investigation of weather effects toward convergence of wired and wireless gigabit services over hybrid free-space optical link

Abstract

We investigate hybrid free-space optical (FSO) link in converged baseband and 60-GHz radio-frequency signals under adverse climate conditions. In this approach, optical double-sideband with carrier method is utilized. The adoption of such an FSO system can be contributed to existing fiber-optic architecture. Managing the signal strength by erbium-doped fiber amplifier, deployment of the system serves the data rate of 2.5 Gb / s to fiber-optic and pico/femto-cellular users concurrently. Our paper studies the impact of rainfall, snowfall, and fog-visibility with the maximum value of 250 mm / h, 10 mm / h, and 1.5 km, respectively. System performance is relatively evaluated for an optical wireless range of 1 km and back-to-back connection. For the bit error rate (BER) of ∼10 − 9, the receiver sensitivity in range of −25.06 to −24.86 dBm for wired and −23.48 to −23.06 dBm for wireless is obtained. The BER analysis shows effective FSO transmission up to 1 km in the rainy season and up to half a kilometer in frequent fog and snow events. The investigation reports the notable power margin for deploying a hybrid optical link in areas where fog or snow impact is higher than rain.