1 - OFDM et CDMA, approche unifiée et méthode de conception de séquences d'étalement adaptées au canal
Bibliographic record
Abstract
In this paper TDMA, CDMA, MC-CDMA and OFDM are presented through an unified formalism. The cyclic prefix insertion is extended to all approaches presented and not only restricted to OFDM. Many fundamental results are highlighted. It is for example shown that if we are looking for a family of orthogonal spreading sequences being yet orthogonal after a one chip delay then we have not another choice than OFDM. Different kind of receivers, involving a same « channel » matrix, are presented : OFDM receiver, Rake receiver and MMSE receiver. All these receivers involve a same channel matrix representing the effect of the propagation channel, the cyclic prefix insertion and its suppression. Finally an algorithm for generating spreading sequences matched to a given propagation channel is introduced. Spreading sequences generated having unequal transmission properties, a power and modulation allocation algorithm is introduced for them. Performances obtained are then very close to those obtained through the OFDM approach.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".