First Simulation#

This tutorial guides you through running a simple communication simulation using comnumpy. You will create a basic QAM communication chain, transmit symbols through an AWGN channel, and evaluate the Symbol Error Rate (SER).

Prerequisites#

Make sure you have installed:

  • numpy

  • matplotlib

  • comnumpy

Step 1: Import Libraries and Define Parameters#

First, import the necessary libraries and define simulation parameters:

import numpy as np
import matplotlib.pyplot as plt
from comnumpy.core import Sequential, Recorder
from comnumpy.core.generators import SymbolGenerator
from comnumpy.core.mappers import SymbolMapper
from comnumpy.core.channels import AWGN
from comnumpy.core.utils import get_alphabet
from comnumpy.core.metrics import compute_ser

img_dir = "../../docs/getting_started/img/"

# parameters
M = 4           # Modulation order (4-QAM)
N = 1000        # Number of symbols
alphabet = get_alphabet("QAM", M)
snr_dB = 10     # Signal-to-Noise Ratio in dB

Step 2: Define Communication Chain#

Define the communication chain using the Sequential class, including symbol generation, mapping, and channel:

# define a communication chain
chain = Sequential([
            SymbolGenerator(M),
            Recorder(name="data_tx"),
            SymbolMapper(alphabet),
            AWGN(value=snr_dB, unit="snr_dB", name="awgn_channel"),
        ])

# test chain
y = chain(N)

Step 3: Run the Chain and Evaluate Performance#

Run the chain and compute the SER to assess system performance:

# estimate performance
data_tx = chain["data_tx"].get_data()
ser = compute_ser(data_tx, y)
print(f"SER = {ser}")

Step 4: Visualize the Received Constellation#

Finally, plot the received symbols to visualize the effect of noise on the constellation:

# plot signals
plt.scatter(np.real(y), np.imag(y))
plt.title("Received Constellation Diagram")
plt.xlabel("In-phase")
plt.ylabel("Quadrature")
plt.grid(True)
Received constellation diagram

Next Steps#

Now that you’ve completed your first simulation, consider exploring:

  • OFDM and MIMO tutorials for advanced communication techniques.

  • The full comnumpy documentation for detailed API reference.

  • Experimenting by changing modulation orders, SNR, and channel models.