Doppler compensation for D-STBC coded time-varying underwater acoustic channels
Bibliographic record
Abstract
In this paper we investigate the performance of distributed space-time block coding (D-STBC) orthogonal frequency division multiplexing (OFDM) over underwater acoustic (UWA) channels. In particular, we consider a relaying system consisting of one source, two relays, and one destination. The relays operate in amplify-and-forward (AF) mode. The underlying channels are assumed to be time-varying frequency selective channels, where the only source of time variation is the relative motion between transceivers. Alamouti D-STBC scheme is used in the second hop, and a two stage receiver is adopted at the destination: in the first stage, multiple resampling (MR) preprocessing of the received signals is performed to minimize the effect of intercarrier interference (ICI), and in the second stage ICI equalization is performed in the frequency domain to further reduce the effect of the residual ICI. To further boost the performance, successive interference cancellation (SIC) is used, where the estimates of the signals at the output of the ICI equalizer are used as tentative decisions. Compared to the single resampling (SR) front end preprocessing, simulation results show the superiority of MR front-end receiver. Also, SIC further boosts the performance, but still, there is a significant gap with respect to the ICI-free limit, when the receiver has perfect knowledge of ICI coefficients and eliminates them completely.
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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 | 0.000 |
| 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 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".