Implementation of CDMA Communication System Simulation in MATLAB Environment

This implementation simulates a CDMA communication system using MATLAB environment. The simulation procedure consists of the following key steps: 1. Random Sequence Generation: Creates pseudo-random binary sequences for spreading using MATLAB's random number generation functions like randi() or randn() for initial data generation. 2. Walsh Code Spreading: Implements orthogonal spreading using Walsh-Hadamard codes through matrix multiplication operations, where each user's data is multiplied by their assigned Walsh code to achieve code division multiple access. 3. BPSK Modulation: Applies Binary Phase Shift Keying modulation using cosine and sine functions, mapping binary 0 and 1 to different phase states (typically 0° and 180°) for carrier modulation. 4. AWGN Addition: Optionally adds Additive White Gaussian Noise using awgn() function or manual noise generation with randn() to simulate realistic channel conditions with controllable SNR levels. 5. BPSK Demodulation: Performs coherent detection using correlation receivers and phase comparison algorithms to recover the baseband signal from modulated carriers under both noisy and noise-free conditions. 6. Walsh Code Despreading: Recovers original data by correlating received signals with respective Walsh codes through inner product operations, utilizing orthogonality properties for interference rejection. 7. Waveform Storage: Records time-domain signals at each processing stage using MATLAB arrays and plotting functions for visualization and analysis of signal transformations. 8. Decoding Comparison: Implements error calculation algorithms using comparison functions like xor() to analyze bit error rates between original and recovered data under different noise conditions. 9. BER vs SNR Plotting: Generates performance curves using semilogy() or plot() functions by systematically varying SNR values and computing corresponding bit error rates to evaluate system performance. This comprehensive simulation implements the complete CDMA communication chain with detailed algorithm explanations and MATLAB function implementations for each processing stage.