in silico
Phase 1 : In Silico Validation
- Objectif
- To rapidly falsify the core mechanism by verifying that for rank-3 channels, the constrained optimization (min ||R_y - H H^H||_F^2 s.t. trace(H H^H) = P_tx) yields exactly two discrete solutions, and that NMSE < -10 dB at SNR ≥ 10 dB and ΔP_tx ≤ 1%.
- Coût estimé
- €500-2000
- Durée estimée
- 4-6 weeks
- Critères de réussite
- NMSE at SNR=10 dB, ΔP_tx=1% for rank-3 channels · NMSE < -10 dB (i.e., 0.1 linear) · (Compute 10*log10(||H_hat - H_true||_F^2 / ||H_true||_F^2) averaged over 10^4 realizations)
- Number of valid solutions for rank-3 channels · Exactly 2 solutions for ≥ 95% of realizations · (Count solutions from the tensor-based solver; report percentage of realizations with exactly 2 solutions)
- NMSE degradation with ΔP_tx (Prediction 2) · ΔNMSE ≤ 3 dB when ΔP_tx increases from 0.5% to 10% at SNR=10 dB · (Compute NMSE(ΔP_tx=10%) - NMSE(ΔP_tx=0.5%) from Monte Carlo curves)
- Condition number relative error (Prediction 3) · Median relative error ≤ 20% at SNR ≥ 10 dB · (One-sample Wilcoxon signed-rank test (one-tailed, α=0.05) against median = 0.2)
- NMSE for rank-4 vs rank-3 (Prediction 4) · NMSE for rank-4 > -5 dB at SNR=20 dB, ΔP_tx=1% · (Mann-Whitney U test (two-tailed, α=0.05) comparing NMSE distributions for r=3 vs r=4)
- On continue si
- All success criteria met: NMSE < -10 dB at SNR=10 dB, ΔP_tx=1%; exactly 2 solutions for ≥ 95% of rank-3 realizations; ΔNMSE ≤ 3 dB; median condition number error ≤ 20%; NMSE for rank-4 > -5 dB.
- On arrête si
- Any of the following: NMSE ≥ -10 dB at SNR=10 dB; fewer than 80% of rank-3 realizations yield exactly 2 solutions; ΔNMSE > 6 dB; median condition number error > 40%; NMSE for rank-4 < -10 dB (indicating method generalizes unexpectedly).
- On réoriente si
- NMSE < -10 dB but number of solutions is >2 for rank-3 (e.g., 4 solutions). Pivot to investigate if the quadratic constraint yields a degenerate intersection (e.g., hypersphere tangent to subspace). If NMSE for rank-4 < -10 dB, pivot to extend the method to higher ranks with additional constraints (e.g., sparsity or smoothness).
- Risques
- The tensor-based solver fails to converge or finds no solutions for rank-3 channels due to numerical instability.Probabilité : mediumParade : Use multiple initializations (10 random starting points) and a robust SDP solver (e.g., CVXPY with MOSEK). If convergence fails, switch to a homotopy continuation method (e.g., Bertini).
- The assumption that rank ≤ 3 holds for 3GPP CDL models is violated (e.g., CDL-E has 12 clusters, effective rank may be >3).Probabilité : mediumParade : Pre-compute effective rank of CDL channels using SVD and threshold at 99% energy. If effective rank >3, reduce to rank-3 via truncated SVD and test method on truncated channels.
- Statistical tests may be underpowered (10^4 realizations may not detect small effect sizes).Probabilité : lowParade : Increase realizations to 10^5 if necessary; use bootstrapped confidence intervals instead of p-values.