def arfcn_to_freq(arfcn, band): """Convert ARFCN to downlink frequency in MHz""" if band == 'GSM850': return 869 + 0.2 * (arfcn - 128) elif band == 'EGSM900': if arfcn <= 124: return 925 + 0.2 * arfcn else: return 935.2 + 0.2 * (arfcn - 124) elif band == 'DCS1800': return 1805 + 0.2 * (arfcn - 512) elif band == 'PCS1900': return 1930 + 0.2 * (arfcn - 512) else: return None

# In a real lab, you would use gr-gsm or pygsm to decode FCCH/SCH print("[REAL SCAN] Using RTL-SDR (ensure gr-gsm installed)") # Placeholder for actual decoding logic # Example: read I/Q samples, detect frequency correction bursts return simulate_gsm_scan() # fallback def save_log(results, filename="gsm_lab_log.json"): """Save results to JSON for lab analysis""" with open(filename, 'w') as f: json.dump(results, f, indent=2) print(f"[LOG] Saved {len(results)} entries to {filename}")

# Perform scan scan_results = real_gsm_scan()