Threshold-Based Adaptive Modulation with Adaptive Subcarrier Allocation in OFCDM-Based 4G Wireless Systems
Bibliographic record
Abstract
Orthogonal frequency and code division multiplexing (OFCDM) is a promising emerging technique for the fourth generation cellular system. In this paper, we propose an adaptive modulation algorithm for OFCDM in order to increase the spectral efficiency without sacrificing the bit error rate (BER) performance. The proposed algorithm is used with an adaptive subcarrier allocation technique which assigns users to subcarriers that produce the best signal to interference and noise ratio (SINR) characteristics while producing minimal multiple access interference to other users. We examine a fixed threshold adaptation algorithm to switch between modulation levels depending upon the estimated SINR. The performance of adaptive modulation in a Rayleigh fading channel for different BER targets is evaluated. The proposed algorithm is shown to provide an increase in throughput and spectral efficiency than using BPSK only. An increase of 47% and 63% in throughput corresponding to a spectral efficiency of 1.47 and 1.63 bits per symbol can be obtained for a target BER of 1% and 10% respectively without increasing the total transmit power.
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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 | 0.001 |
| 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) | 0.000 | 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".