Latency-constrained fading mitigation for coherent optical feeder links based on space-time-frequency coding
conference paper
Optical feeder links (OFLs) benefit from the vast amount of bandwidth available in the THz-regime of the electromagnetic spectrum, and can be considered as enablers for future terabit-per-second satellite systems. A particular challenge for OFLs is to mitigate the effects of fading, caused by a combination of turbulence-induced scintillation, beam wander and pointing errors. The conventional solution is to exploit temporal diversity by a combination of interleaving and forward error correction (FEC). In this study we present an overview of fading mitigation techniques for latency-constrained coherent ground-to-satellite OFL and contribute a generic model which combines various diversity schemes including temporal, spatial, frequency and site diversity. To unlock spatial diversity, multi-beam space-time block coding and multi-beam, multi-λ are proposed and simulated. Though space-time block coding (STBC) provides more diversity gain, it requires accurate timing synchronization at the transmitter and channel state information at the receiver. Temporal, frequency and site diversity all rely on some form of interleaving and the potential diversity, pros and cons of each of these diversity techniques are covered in the presented study. In general, with a strict latency constraint and a tight link budget, frequency diversity, spatial diversity - either by STBC or multi-beam multi-λ - and site diversity can be effective methods to mitigate the effects of fading and close the link budget.
Topics
TNO Identifier
990155
ISSN
0277786X
ISBN
9781510668034
Publisher
SPIE
Article nr.
127774T
Source title
ICSO 2022, International Conference on Space Optics, Dubrovnik, Croatia, 3–7 October 2022
Editor(s)
Minoglou, K.
Karafolas, N.
Cugny, B.
Karafolas, N.
Cugny, B.
Collation
13 p.
Files
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