On spreading codes for the down-link in a multiuser MIMO/OFDM system
Bibliographic record
Abstract
We propose a method for multiple access using multiple antennas at both ends of the communication link (MIMO) and orthogonal frequency division multiplexing (OFDM). The MIMO component of the system serves to increase bandwidth efficiency, whereas the OFDM component tackles the frequency selectivity of most practical channels. The unique feature of the proposed design is that it is based on direct sequence spread spectrum, except that the spreading codes are defined in the space and frequency domains, rather than the time domain. With second-order channel knowledge at the transmitter, this allows for power allocation schemes over spatial and frequency channels; without any knowledge of the channel, exploitation of frequency diversity is still an inherent feature. Lastly, OFDM is known to be simpler to implement than time-domain equalization, and therefore the proposed scheme is more practically feasible than competing schemes based on equalization.
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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".