IEEE photonics journal · 2014 · 114 citations · 26 references
EngineeringCommunicationElectrical EngineeringInformation TheoryPropagationWireless CommunicationsAtmospheric OpticsChannel CapacityDiversity TechniquesFree-space OpticsOptical Communication SystemsWireless Channel ModelingAtmospheric TurbulenceBit Error RateDiversity OrderFadingFree-space Optical CommunicationMultiuser DiversityOutage ProbabilityTurbulence-induced Fading
Free‑space optical communication offers cost‑effective high‑rate links, but turbulence‑induced fading restricts its use to short ranges. The study proposes a multiuser diversity FSO scheme that selects the Nth best user to exploit channel fluctuations for a selection diversity gain. The authors analyze the system’s statistics over weak and strong atmospheric turbulence, deriving outage probability, bit‑error rate, average capacity, diversity order, and coverage. They find that for gamma‑gamma fading the diversity order equals N min{α, β}/2, where α and β are the channel fading parameters.
Free-space optical (FSO) communication has become a cost-effective method to provide high data rates. However, the turbulence-induced fading limits its application to short-range applications. To address this, we propose a multiuser diversity (MD) FSO scheme in which the Nth best user is selected and the channel fluctuations can be effectively exploited to produce a selection diversity gain. More specifically, we first present the statistics analysis for the considered system over both weak and strong atmospheric turbulence channels. Based on these statistics, the outage probability, bit-error rate performance, average capacity, diversity order, and coverage are analyzed. Results show that the diversity order for the gamma-gamma fading is N min{α, β}/2, where N is the number of users, and α and β are the channel fading parameters related to the effective atmospheric conditions of the link.
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