EC09 · Sem 6 · Digital communication

BPSK over AWGN: BER vs Eb/N0

Aim: Measure the bit error rate of BPSK by Monte Carlo and compare with theory.

🧪 Live simulation🧊 Real-time 3D bench⚠ Simulated values, not physical measurements

🔬 Virtual lab

Starting the lab…

📘 Theory

BPSK sends one bit per symbol as ±1. Gaussian noise spreads the received points; errors occur when noise pushes a point across zero. The theoretical BER is ½·erfc(√(Eb/N0)).

BER = ½·erfc(√(Eb/N0))

🧰 Apparatus (virtual)

BPSK modulator
AWGN channel
detector
BER counter

📝 Procedure

Run at 8 dB and read the simulated BER
Lower Eb/N0 to 2 dB and watch the cloud spread
Compare every point with the theory curve
Find the Eb/N0 needed for BER = 10⁻⁵

Observations and result (kept on this device)

🎤 Viva questions

About what Eb/N0 gives BER 10⁻⁵ for BPSK

About 9.6 dB.

Why do we use Monte Carlo simulation

Real systems are too complex for closed-form BER.

🛡️ Safety

Virtual lab. With real RF equipment, respect exposure limits, never transmit without a licence, and keep antennas away from people.