Rateless Codes Performance Analysis in Correlated Channel Model for GEO Free Space Optics Downlinks

Autor: ANDO', Andrea, BUSACCA, Alessandro, CURCIO, Luciano, MANGIONE, Stefano, GALLO, Pierluigi, Messineo, G
Přispěvatelé: Andò, A, Busacca, A, Curcio, L, Mangione, S, Messineo, G, Gallo, P
Jazyk: angličtina
Rok vydání: 2012
Předmět:
Settore ING-INF/03 - Telecomunicazioni
Free Space Optics (FSO) technologies for satellite communications offer several advantages: wide bandwidth
high rate capability
immunity to electromagnetic interference and small equipment size. Thus
they are suitable for inter-satellite links
deep space communications and also for high data rate ground-to-satellite/satellite-to-ground communications. Nevertheless
FSO links suffer impairments that cause power signal degradation at the receiver. Scattering and absorption cause power signal attenuations predictable by suitable deterministic models. Optical turbulence causes random irradiance fluctuations which can generate signal fading events and can thereby only be predicted by statistical models. Attenuation and fading events can corrupt FSO links
and so it would be recommended to add mitigation error codes on the communication link. FSO channel can be described as an erasure channel: fading events can cause erasure errors. We have identified in rateless codes (RCs) a suitable solution to be employed in FSO links. RCs do not need feedback and they add a redundant coding on the source data that allows the receiver to recover the whole payload
despite erasure errors. We implemented two different of rateless codes: Luby Transform (LT) and Raptor. We analyzed their performances on a simulated turbulent GEO FSO downlink (1 Gbps - OOK modulation) at a 1
06 μm wavelength and for different values of zenith angles. Assuming a plane-wave propagation and employing Hufnagel-Valley
we modeled the downlink using: 1) a temporal correlated channel model based on Gamma-Gamma probability distribution and 2) an irradiance covariance function that we converted on a time function using Taylor frozen eddies hypothesis. Our new channel model is able to simulate irradiance fluctuations at different turbulence conditions as it will be shown in the full paper. We will also report performance results of LT and Raptor codes at overhead range varying between 0 and 50% and for different values of source packets
Settore ING-INF/01 - Elettronica
Databáze: OpenAIRE
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