| # CISR24 generation algorithm |
|
|
| The MATLAB implementation in `matlab/generate_cisr24_dataset.m` is the |
| executable source of truth. This pseudocode documents its release contract. |
|
|
| ```text |
| for split_id, split in [train, val, test]: |
| for class_id, waveform specification in classes.csv order: |
| for snr_id, snr_db in [-20, -18, ..., 20]: |
| for local_sample_id in [1, ..., count(split)]: |
| seed = 20260410 |
| + 30000000 * split_id |
| + 1000000 * class_id |
| + 10000 * snr_id |
| + local_sample_id |
| rng(seed, "twister") |
| |
| parameters = draw only from the paper's class-specific sets |
| burst = generate_complex_baseband_waveform(class_id, parameters) |
| burst = burst * exp(j * uniform(0, 2*pi)) |
| burst = burst / sqrt(mean(abs(burst)^2)) |
| |
| start = uniform_integer(0, 1024 - len(burst)) |
| record = complex_zeros(1024) |
| record[start : start + len(burst)] = burst |
| |
| noise_power = 10^(-snr_db / 10) |
| noise = sqrt(noise_power / 2) * (randn(1024) + j*randn(1024)) |
| record = record + noise |
| |
| append float32 [I, Q] to /iq |
| append class_id, snr_db, and global sample index to HDF5 |
| append seed, support, taxonomy, and waveform parameters to manifest |
| ``` |
|
|
| `split_id`, `class_id`, and `snr_id` are zero based in the formula. The local |
| sample ID is one based. The resulting 705,600 seeds are unique and remain below |
| the `uint32` limit. |
|
|
| ## Physical conformance rules |
|
|
| - Linear PSK/QAM uses RRC shaping with `sps=4`, `Rs=2.5 Msps`, span 8, and |
| beta in `{0.25, 0.35}`. |
| - 4FSK/8FSK uses CPFSK `h=0.5`, `sps=8`, and `Rs=1.25 Msps`, giving actual |
| adjacent tone spacing `0.625 MHz`. |
| - GMSK and LFM-GMSK use `BT=0.3`, pulse length 4, and `sps=4`. |
| - OFDM-LFM chirp-enhanced carriers use a centered time coordinate and symmetric |
| sweep around each subcarrier. Generation aborts if instantaneous frequency |
| reaches Nyquist. |
| - Barker and Costas distribute the selected paper active length across chips by |
| at most one sample and record the actual minimum/maximum chip width. |
|
|
| ## Completion semantics |
|
|
| Generation starts with `generation_status=in_progress`. A successful generator |
| sets it to `complete` and records exactly 705,600 samples. External packaging |
| keeps `.INCOMPLETE` until validation, full-grid SNR checks, shortcut audit, |
| paper alignment, loader tests, checksums, and the release gate all pass. |
|
|
