Performance Analysis of Subcarrier Allocation in Two Dimensionally Spread OFCDM Systems
Bibliographic record
Abstract
Orthogonal frequency code division multiplexing (OFCDM) has recently been introduced as a candidate for 4th generation wireless systems. This signalling scheme utilizes code spreading in the time and frequency domains simultaneously to improve frequency diversity and minimize MAI simultaneously. As a result, it is capable of outperforming multicarrier CDMA systems that employ one-dimensional spreading. In this paper, a novel adaptive subcarrier allocation algorithm is developed for OFCDM to improve the overall BER performance for all spreading configurations. This algorithm assigns users to subcarrier groups that provide favorable fading characteristics, while simultaneously reducing the amount of interference caused to other users. The proposed algorithm is shown to provide a performance improvement ranging from 1.5 dB with 2times16 spreading, to 7 dB with 16times2 spreading. The algorithm is also shown to maintain or improve the BER floor for each OFCDM spreading configuration.
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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 | 0.007 |
| 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 | 0.000 | 0.001 |
| 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".