OFDM System Simulation (MATLAB)

This project implements a complete Orthogonal Frequency Division Multiplexing (OFDM) transmit–receive chain using FFT/IFFT-based signal processing. It demonstrates how digital data can be encoded, transmitted over noisy channels, and recovered with high accuracy.

Key Features

• 16-QAM modulation and demodulation
• 64-point FFT/IFFT based OFDM waveform generation
• Cyclic prefix insertion for multipath resistance
• Pilot subcarriers for phase error correction
• AWGN channel model (SNR = 15 dB)
• BER, PAPR, spectrum, and constellation analysis

System Parameters

Parameter	Value
FFT Size	64
Data Subcarriers	48
Pilot Subcarriers	4
Cyclic Prefix Length	16
Modulation Scheme	16-QAM
Channel	AWGN (15 dB SNR)
OFDM Symbols	10

Workflow

1. Generate random bits
2. Map bits to 16-QAM symbols
3. Insert data + pilot subcarriers
4. Perform IFFT → time-domain OFDM signal
5. Add cyclic prefix and transmit through AWGN
6. Remove CP and perform FFT at receiver
7. Use pilot tones for phase correction
8. Demodulate and recover transmitted bits
9. Evaluate BER and visualize results

Output Highlights

Metric	Result
Bit Error Rate (BER)	~0.0026
Errors per transmission	5–30 bits (varies with noise)
PAPR	~8.2 dB
Constellation	Clear 16-QAM clusters with minor noise spread

Visualizations Produced

• Time-domain transmitted waveform
• Transmitted spectrum (subcarrier structure)
• Received spectrum (noise effects visible)
• Recovered 16-QAM constellation plot

How to Run

1. Open MATLAB
2. Place all .m files in the same folder
3. Run:

ofdm_simulation