On the Performance of OFDM Systems Over a Cartesian Clipping Channel: A Theoretical Approach
Bibliographic record
Abstract
We introduce an accurate theoretical approach for computing the symbol-error rate (SER) of an M-ary quadrature amplitude modulation (M-QAM) orthogonal frequency division-multiplexing (OFDM) system in the Nyquist rate Cartesian clipping channel. The Cartesian clipper clips the high peak values of the Nyquist rate in-phase/quadrature (I/Q) components of the complex baseband OFDM signal separately. In contrast to previous works that approximate the nonlinear noise, in the frequency domain, as a Gaussian additive random process, an accurate expression is derived for the probability density function (pdf) of the clipping noise at the output of the OFDM demodulator on each subcarrier. The inverse Fourier transform of the characteristic function of the noise is used to derive this accurate pdf. Using this pdf, we can evaluate the performance of the OFDM system for each subcarrier with high accuracy, especially at high backoffs where the Gaussian approximation of the nonlinear noise is no longer valid. The proposed method has the accuracy and validity of the simulation while being comparatively much less time consuming.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.002 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 teacher head, 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".