Direct Sequence Spread Spectrum Communication System with Interference

This direct sequence spread spectrum communication system with interference employs m-sequence generators to produce PN codes that undergo transmission through an additive white Gaussian noise (AWGN) channel. The received signal at the receiver consists of "useful signal + AWGN + interference." We implement despreading and decision operations on the received signal to obtain user signal detection results. The despreading process involves correlating the received signal with locally generated PN sequences using matched filter techniques, while decision making employs threshold comparators for binary signal recovery. We then plot BER versus Eb/N0 ratio curves under different spreading gains (10, 30, and 50), implemented through variable-length PN sequence modulation. These curves, generated using Monte Carlo simulation methods with iterative SNR sweeping, help analyze system performance under various signal-to-noise ratio conditions, particularly demonstrating how increased processing gain enhances interference immunity and reduces bit error rates.