Raptor-Coded Free-Space Optical Communications Experiment
Bibliographic record
Abstract
While free-space optical (FSO) links have many inherent advantages, such as high data rates and license-free operation, they are sensitive to atmospheric conditions. A promising solution to improve the reliability of such communication links is to combine FSO and radio frequency (RF) channels using Raptor codes. This paper presents a first in-field demonstration of real-time Raptor-coded FSO communication over a 1.87 km urban link. This work serves as an important initial step toward field-programmable gate array (FPGA)-based implementation of Raptor-coded hybrid FSO/RF links. The hardware architecture of a Raptor 10 decoder based on a novel resource- and time-efficient matrix inversion algorithm is presented and implemented in an FPGA platform. The receiver is implemented in a pipelined architecture to maximize link utilization. The throughput of the Raptor-coded FSO link is measured both experimentally and numerically under real-life weather conditions for a continuous period of 8 h. Experimental results demonstrate that Raptor-coded FSO links are capable of tracking changes in the channel state to maximize link utilization.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".