Create backend/comm_system.py

backend/comm_system.py

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+import numpy as np
+
+def simulate_channel(snr_db: float, num_symbols: int = 200):
+    # 1. Generate 16-QAM Constellation points (+/-1, +/-3)
+    constellation = np.array([complex(i, j) for i in [-3, -1, 1, 3] for j in [-3, -1, 1, 3]])
+    
+    # 2. Transmit ideal symbols
+    ideal_symbols = np.random.choice(constellation, num_symbols)
+    
+    # 3. Probability Math: Calculate noise power based on SNR limit
+    signal_power = np.mean(np.abs(constellation)**2) # Avg power of 16-QAM
+    snr_linear = 10 ** (snr_db / 10)
+    noise_power = signal_power / snr_linear
+    
+    # 4. Inject Gaussian Noise (AWGN)
+    noise = np.sqrt(noise_power / 2) * (np.random.randn(num_symbols) + 1j * np.random.randn(num_symbols))
+    noisy_symbols = ideal_symbols + noise
+    
+    # Return data formatted for the React UI Plotly graph
+    return {
+        "ideal_i": ideal_symbols.real.tolist(),
+        "ideal_q": ideal_symbols.imag.tolist(),
+        "noisy_i": noisy_symbols.real.tolist(),
+        "noisy_q": noisy_symbols.imag.tolist()
+    }