BPSK Modulation and Demodulation with Direct Sequence Spread Spectrum System Source Code

This document provides comprehensive details about BPSK modulation and demodulation along with complete source code implementation for a BPSK-based Direct Sequence Spread Spectrum (DSSS) system. The implementation includes comparative analysis of Bit Error Rate (BER) performance under both white noise and Rayleigh fading channel conditions. BPSK (Binary Phase Shift Keying) represents a fundamental digital modulation technique widely employed in digital communication systems. Our technical discussion covers the underlying principles of BPSK modulation and detailed implementation methodologies for both modulation and demodulation processes. The provided source code features modular implementation with key components including: - Signal mapping module converting binary data to BPSK symbols (±1 representation) - Spreading sequence generator using pseudo-random noise (PN) codes - Digital mixer for spectrum spreading operations - Channel simulation modules for AWGN and Rayleigh fading environments - Correlation-based despreading and detection algorithms - BER calculation and statistical analysis functions Each code module includes comprehensive inline documentation explaining algorithm implementation, critical parameters, and functional relationships. The implementation demonstrates practical considerations such as synchronization techniques, matched filtering, and decision threshold optimization. Through comparative BER analysis under different channel conditions, we evaluate BPSK system performance characteristics, highlighting both operational advantages and limitations. The performance comparison provides insights into system robustness, highlighting the impact of fading channels on communication reliability and suggesting potential enhancement strategies for real-world deployment scenarios.