Signal Detection for Orthogonal/Quasi-Orthogonal Space-Frequency Block Coded OFDM Transmit Diversity Schemes
Bibliographic record
Abstract
The combination of space-time block coding (STBC) and orthogonal frequency division multiplexing (OFDM) has drawn much attention in recent years. However, the application of conventional STBC decoding for OFDM renders poor performance due to high channel gain variation across the STBC codeword. In this paper, we propose a square root and division free recursive QR (SDRQR) decomposition based detector for STBC coded OFDM systems that utilize four transmit antennas. The proposed detection scheme is applied to both orthogonal and quasi-orthogonal STBCs. Performance of the proposed detector is evaluated semi-analytically and compared with results obtained from exact link simulations. Our analyses show an excellent performance gain attained by SDRQR compared to previously proposed solutions. It is also shown that the relative computational complexity of the proposed detector is justified by the performance gain it attains over the previous solutions
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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 | 0.004 |
| 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 | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".