Optical OOK-CDMA and PPM-CDMA systems with turbo product codes
Bibliographic record
Abstract
The application of turbo product codes (TPC) in intensity-modulated direct-detection optical code-division multiple-access (CDMA) systems with ON-OFF keying or binary pulse-position modulation is proposed in this study. Optical multiple-access interference caused by other users is the main source of noise that degrades system performance and limits the total number of active users in an optical CDMA system. In this work, the original turbo product decoding algorithm is modified according to the binary memoryless channel model. It is shown that the implementation of TPCs in an optical CDMA system provides significant improvement of the bit-error rate, hence, permitting a higher number of active users with optical orthogonal codes (OOC) of less weight. The proposed TPC has about 20% overhead, but the reduction in the weight of the OOC reduces the system bandwidth to less than half to that of the comparable uncoded system.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".